Light-emitting device, light-emitting apparatus, image display apparatus, method of manufacturing light-emitting device, and method of manufacturing image display apparatus

ABSTRACT

Light-emitting devices, light-emitting apparatuses, image display apparatuses and methods of manufacturing same are provided. The devices and apparatuses include a transparent electrode that is connected directly to light output surfaces so as to cover the whole areas of the light output surfaces. The transparent electrode is formed to be larger in area than the light output surfaces, and are securely electrically connected to n-type semiconductor layers including the light output surfaces.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/799,309 filed on Mar. 12, 2004, which claims priority to applicationof Japanese Patent Application Nos. P2003-069602 filed Mar. 14, 2003,and P2004-009777 filed Jan. 16, 2004, the disclosures of which areherein incorporated by reference.

BACKGROUND

The present invention relates to a light-emitting device, alight-emitting apparatus, an image display apparatus, a method ofmanufacturing a light-emitting device, and a method of manufacturing animage display apparatus. More particularly, the present inventionrelates to a light-emitting device, a light-emitting apparatus, an imagedisplay apparatus, a method of manufacturing a light-emitting device,and a method of manufacturing an image display apparatus in which lightemission efficiency is prevented from being lowered and an electrode isformed for minute light-emitting device main bodies with high accuracy.

At present, in electronic apparatuses and the like, there have beenwidely used those configured by arranging a multiplicity of minutedevices, electronic component parts, electronic devices, and electroniccomponent parts obtained by embedding these in an insulator such as aresin. For example, in the case of assembling an image display apparatusby arranging light-emitting devices in a matrix form, conventionally,there has been practiced a method of forming the devices directly on asubstrate as in the cases of a Liquid Crystal Display apparatus (LCD)and a Plasma Display Panel (PDP) or a method of arranging singleLight-Emitting Diode (LED) packages as in the case of an LED display.

Besides, since LEDs as light-emitting devices are expensive, an imagedisplay apparatus using the LEDs can be manufactured at low cost bymanufacturing a large number of LED chips from one sheet of wafer.Namely, when the LEDs are miniaturized from the conventional size ofabout 300 μm square to a size of several tens of micrometers square andare connected to produce an image display apparatus, it is possible tolower the price of the image display apparatus. An electrode for such aminute light-emitting device is in many cases produced by a method inwhich a metallic film is formed as the electrode at a part of a lightoutput surface of a light-emitting device main body, and the electrodeis connected to a wiring through a metallic film or a gold wire.

On the other hand, the light-emitting device is electrically connectedto a wiring for driving the light-emitting device, and emits light froma predetermined light emission region to the exterior of the device.Therefore, it is important to prevent the light output efficiency frombeing lowered, by ensuring that the light emitted from the lightemission region to the exterior of the device is not shielded by thewiring and/or the electrode formed in the light emission region. In viewof this, for example, in relation to light-emitting devices such as aplanar light-emitting thyristor and an organic EL device, there has beenknown a technology of forming a transparent electrode so as not toshield the light emitted from the light emission region (see, forexample, Japanese Patent Laid-open No. Hei 9-283801, and Japanese PatentLaid-open No. 2002-260843).

However, it is difficult to form an electrode accurately at the lightoutput surface in a minute light-emitting device. For example, in thecase of forming an electrode for a minute light-emitting device mainbody in which the size of the light output surface is about 10 μm squareor below, an accuracy of within about 10 μm is needed for alignmentbetween the light output surface and the electrode. Besides, even in thecase where an electrode is formed at the light output surface by use ofa light-transmitting material so as not to lower the light outputefficiency, also, the formation of the electrode accurately at the lightoutput surface becomes more difficult as the size of the light-emittingdevice becomes smaller. Furthermore, as the size of the light-emittingdevice is reduced, the connection between the electrode and thelight-emitting device main body would become insufficient, possiblyleading to a trouble in driving the light-emitting device.

SUMMARY

The present invention has been made in consideration of the aboveproblems. In an embodiment, the present invention provides alight-emitting device, a light-emitting apparatus, an image displayapparatus, a method of manufacturing a light-emitting device, and amethod of manufacturing an image display apparatus in which light outputefficiency concerning the light emitted from a light-emitting devicemain body is enhanced even in the case of a minute light-emitting deviceand a required electrode is securely formed for the light-emittingdevice main body.

In accordance with a first aspect of the present invention in anembodiment, there is provided a light-emitting device including alight-emitting device main body having a light output surface andtransferred, and a transparent electrode formed in a size larger thanthe size of the light output surface so as to cover the light outputsurface and connected directly to the whole area of the light outputsurface. According to the light-emitting device, even where thelight-emitting device is minute in size, it is possible to accuratelyconnect the transparent electrode and the light output surface to eachother, and to suppress the possibility of various troubles such ascontact failure in driving the light-emitting device. Furthermore, thetransparent electrode does not shield the light emitted from the lightoutput surface, and the light output efficiency can be enhanced, ascompared with the case where the light is shielded by a metallicelectrode.

In the light-emitting device as above, the transparent electrode in anembodiment preferably provides direct connection between a wiring forsupplying electric power to the light-emitting device main body and thelight-emitting device main body. According to such a transparentelectrode, it is unnecessary to connect the electrode formed for thelight-emitting device main body to the wiring through a separatelyformed connection wire, and the direct connection between thelight-emitting device and the wiring through the transparent electrodepromises accurate connection between the electrode and the wiring evenwhere the light-emitting device is minute in size.

In accordance with a second aspect of the present invention in anembodiment, there is provided a light-emitting device including alight-emitting device main body having a light output surface, and atransparent electrode formed in a size larger than the size of the lightoutput surface so as to cover the light output surface. Thelight-emitting device main body is provided in the form of a chipcomposed of a plurality of semiconductor layers, and the transparentelectrode is connected directly to the whole area of the light outputsurface and connected to side surfaces of the semiconductor layerincluding the light output surface. According to such a light-emittingdevice, particularly, the ratio of the area of the side surfaces to thearea of connection between the transparent electrode and thelight-emitting device main body is relatively increased as thelight-emitting device becomes more minute in size. Therefore, by formingthe transparent electrode not only on the light output surface but alsoon the side surfaces, it is possible to increase the area of connectionbetween the light-emitting device main body and the transparentelectrode, and to enhance the reliability of the connection conditionbetween the light-emitting device main body and the electrode.

Further, in the light-emitting device as above, the transparentelectrode in an embodiment is preferably connected to the side surfacesof the semiconductor layer including the light output surface through acontact layer. According to such a light-emitting device, by making theconnection through the contact layer, it is possible to further enhancethe connection performance between the transparent electrode and thelight-emitting device main body, and to provide a light-emitting devicehaving high reliability.

In addition, in the light-emitting device as above, preferably, therefractive index of the transparent electrode in an embodiment is lowerthan the refractive index of the semiconductor layer including the lightoutput surface and is higher than the refractive index of a resin layerformed on the upper side of the transparent electrode. According to sucha transparent electrode, light output efficiency can be enhanced, ascompared with the case where light is reflected at the interface betweenthe light-emitting device main body and a resin layer directly coveringthe light-emitting device main body.

Furthermore, in the light-emitting device as above, the transparentelectrode is preferably formed by coating the light output surface witha paste containing conductive particulates dispersed in alight-transmitting resin. By applying such a paste directly to the lightoutput surface of the light-emitting device, it is possible to connectthe light-emitting device main body and the transparent electrode toeach other while generating little gap therebetween. Further, when thepaste is applied, the paste goes round onto the side surfaces of thelight-emitting device main body, whereby the light-emitting device mainbody and the transparent electrode can be securely connected to eachother.

Furthermore, in the light-emitting device as above, preferably, theconductive particulates scatter the light emitted from the light outputsurface and diffuse the light from the transparent electrode to theexterior of the device. Such conductive particulates can scatter thelight coming into the transparent electrode and diffuse the light to awide range, so that the light can be emitted from the light outputsurface to a wide range. Therefore, even if the light-emitting device isminute in size, the light-emitting device can have an apparent lightemission surface greater than the actual size of the light-emittingdevice.

In accordance with a third aspect of the present invention in anembodiment, there is provided a light-emitting device including alight-emitting device main body having a light output surface, and atransparent electrode formed in a size larger than the size of the lightoutput surface so as to cover the light output surface and connecteddirectly to the whole area of the light output surface. According tosuch a light-emitting device, it is possible to accurately connect thetransparent electrode and the light output surface to each other evenwhere the light-emitting device is minute in size, and it is possible toenhance light output efficiency, as compared with the case where ametallic electrode is formed.

In accordance with a fourth aspect of the present invention in anembodiment, there is provided a light-emitting apparatus including aplurality of light-emitting device main bodies each having a lightoutput surface and transferred, and a transparent electrode formed to belarger in a size than the light output surfaces so as to cover the lightoutput surfaces and connected directly to the whole areas of the lightoutput surfaces. In such a light-emitting apparatus, even where thelight-emitting device main bodies are minute in size, the transparentelectrode formed to be larger in size than the light-emitting devicesensures that the transparent electrode can be easily connected to eachof the light output surfaces, without accurately forming the transparentelectrode relative to the positions of the individual light-emittingdevices.

In the light-emitting apparatus as above, preferably, the transparentelectrode in an embodiment is formed collectively on the light outputsurfaces of the plurality of light-emitting device main bodies.Therefore, the electrode can be formed on the light output surfaceseasily and securely, without forming the electrode individually for eachof the light-emitting device main bodies.

Further, in the light-emitting apparatus as above, preferably, thetransparent electrode in an embodiment is formed by coating the lightoutput surfaces with a paste containing conductive particulatesdispersed in a light-transmitting resin. When such a paste is used, theconductive particulates dispersed in the paste make contact with eachother in the transparent electrode and, further, make contact with thelight output surfaces, too. Therefore, electrical connection between thelight output surfaces and the electrode can be secured.

Furthermore, in the light-emitting apparatus as above, preferably, theconductive particulates in an embodiment scatter the light emitted fromthe light output surfaces and diffuse the light from the transparentelectrode to the exterior of the apparatus. With such conductiveparticulates, it is possible to diffuse to a wide range the lightemitted from the light-emitting device main bodies provided as minutelight sources, and to emit the light from the whole region of the lightemission surface of the light-emitting apparatus.

In accordance with a fifth aspect of the present invention in anembodiment, there is provided an image display apparatus including animage display surface formed by arranging a plurality of light-emittingdevices on an apparatus substrate, each of the light-emitting devicesincluding a light-emitting device main body having a light outputsurface and transferred, and a transparent electrode formed in a sizelarger than the size of the light output surface so as to cover thelight output surface and connected directly to the whole area of thelight output surface. According to such an image display apparatus, evenwhere each of the light-emitting device main bodies is minute in size, alarger apparent light emission surface can be obtained, so that lightcan be emitted from the whole part of the image display surface andimage quality can be thereby enhanced.

In accordance with a sixth aspect of the present invention in anembodiment, there is provided a method of manufacturing a light-emittingdevice, including the steps of transferring a light-emitting device mainbody having a light output surface onto a resin portion so as to exposethe light output surface, forming a resist film on the light outputsurface and the surface of the resin portion, providing the resist filmwith an opening portion larger in size than the light output surface sothat the opening portion fronts on the light output surface, and forminga transparent electrode in the opening portion so that the transparentelectrode is connected directly to the whole area of the light outputsurface. With the transparent electrode formed in such an openingportion, the transparent electrode can be formed directly for thelight-emitting device so as to cover the light output surface, and thetransparent electrode can be formed for each light-emitting deviceeasily and securely, without conducting alignment for accurately forminga transparent electrode for a minute light-emitting device.

Further, in the method of manufacturing a light-emitting device as abovein an embodiment, preferably, the opening portion is so formed as tofront on a wiring for supplying electric power to the light-emittingdevice main body, and the light output surface and the wiring areconnected directly to each other through the transparent electrode. Withsuch a transparent electrode, the light-emitting device main body andthe wiring can be connected directly to each other. Therefore, where thelight-emitting device is minute in size, the light-emitting device mainbody and the wiring can be securely connected to each other withoutseparately forming a connection wire with high accuracy.

In accordance with a seventh aspect of the present invention in anembodiment, there is provided a method of manufacturing a light-emittingdevice, including the steps of forming a resist film on a light outputsurface of a light-emitting device main body, providing the resist filmwith an opening portion larger in size than the light output surface sothat the opening portion fronts on the light output surface, and forminga transparent electrode in the opening portion so that the transparentelectrode is connected directly to the whole area of the light outputsurface. According to such a method of manufacturing a light-emittingdevice, the transparent electrode can be formed accurately, withoutconducting alignment for forming the transparent electrode for thelight-emitting device.

In accordance with an eighth aspect of the present invention in anembodiment, there is provided a method of manufacturing an image displayapparatus, including the steps of transferring, fixing, and disposing aplurality of light-emitting device main bodies each having a lightoutput surface onto a resin portion so as to expose the light outputsurfaces, forming a resist film on the light output surfaces and thesurface of the resin portion, providing the resist film with an openingportion larger in size than the light output surfaces so that theopening portion fronts on the light output surfaces, and forming atransparent electrode in the opening portion so that the transparentelectrode is connected directly to the whole areas of the light outputsurfaces. According to such a method of manufacturing an image displayapparatus, the transparent electrode can be formed for eachlight-emitting device, without conducting alignment for forming thetransparent electrode for the individual light-emitting devices.

In the method of manufacturing an image display apparatus as above in anembodiment, preferably, the opening portion is so formed as to front ona wiring for supplying electric power to the plurality of light-emittingdevice main bodies, and the light output surfaces and the wiring areconnected to each other collectively through the transparent electrode.Therefore, even in the case of an image display apparatus in which aplurality of light-emitting devices are arranged, the connection betweenthe wiring and each of the devices can be easily achieved withoutlowering the light output efficiency.

In accordance with a ninth aspect of the present invention in anembodiment, there is provided a light-emitting apparatus including: alight-emitting device including a light-emitting device main body havinga light output surface and transferred, and a contact metal formed onthe light output surface; a wiring layer formed outside the region ofthe light output surface; and a transparent electrode so formed as tocover the contact metal and the wiring layer. With the transparentelectrode so formed as to cover the contact metal and the wiring layer,electrical connection between the contact metal and the wiring layer canbe securely achieved.

In the light-emitting apparatus as above in an embodiment, preferably,the transparent electrode is larger in size than the light outputsurface and is connected directly to the whole area of the light outputsurface. Since the light emitted from the light-emitting device is notshielded by the transparent electrode but emitted to the exterior of thelight-emitting apparatus, it is possible to enhance light outputefficiency, as compared with the case where the transparent electrode isformed with the same dimension of the light output surface, and tothereby enhance display characteristics of the light-emitting apparatus.

In the light-emitting apparatus as above in an embodiment, the surface,making contact with the transparent electrode, of the contact metal ispreferably formed of a noble metal. With the outermost surface of thecontact metal formed of a noble metal, it is possible to preventoxidation of the contact metal in the region of contact with thetransparent electrode. This makes it possible to prevent the troublethat the contact metal might be deteriorated due to corrosion with theresult of an increase in electric resistance thereof.

In the light-emitting apparatus as above in an embodiment, the surface,making contact with the transparent electrode, of the wiring layer ispreferably formed of a noble metal. With the outermost surface of thewiring layer formed of a noble metal, it is possible to preventoxidation of the wiring layer in the region of contact with thetransparent electrode. This makes it possible to prevent the troublethat the wiring layer might be deteriorated due to corrosion with theresult of an increase in electric resistance thereof.

Preferably, the light-emitting apparatus in an embodiment as abovefurther includes a protective resin layer so formed as to cover thetransparent electrode. With the protective resin layer so provided as tocover the transparent electrode, it is possible to prevent thetransparent electrode from being deformed or deteriorated.

Preferably, the light-emitting apparatus in an embodiment as abovefurther includes a diffusion preventive layer for preventing mutualdiffusion of a component of the protective resin layer and a componentof the transparent electrode, between the protective resin layer and thetransparent electrode. With a resin sheet as the diffusion preventivelayer sandwiched between the transparent electrode and the protectiveresin layer, it is possible to prevent mutual diffusion of componentsbetween the transparent electrode and the protective resin film, and toprevent the conductivity of the transparent electrode from beingdeteriorated.

In accordance with a tenth aspect of the present invention in anembodiment, there is provided a method of manufacturing a light-emittingapparatus, including the steps of transferring a light-emitting devicemain body having a light output surface onto a resin portion so as toexpose the light output surface, forming an electrode separation wall onthe surface of the resin portion, providing the electrode separationwall with an opening portion larger in size than the light outputsurface so that the opening portion fronts on the light output surface,forming a wiring layer on the surface of the resin portion in the insideof the opening portion, and forming a transparent electrode in theopening portion so that the transparent electrode is connected directlyto a contact metal formed on the light output surface and to the wiringlayer. With the transparent electrode so formed as to cover the contactmetal and the wiring layer, it is possible to securely achieveelectrical connection between the contact metal and the wiring layer. Inaddition, since it is unnecessary to form the wiring layer in contactwith the contact metal, it is possible to lower the positioning accuracyin forming the wiring layer and to enhance operating efficiency, ascompared with the case of forming the wiring layer in contact with thecontact metal, which is minute in size.

In the method of manufacturing a light-emitting apparatus as above in anembodiment, the wiring layer is preferably formed outside the region ofthe light output surface. With the wiring layer formed outside theregion of the light output surface, it is possible to reduce the amountof light shielded by the wiring layer, of the light emitted from thelight-emitting device, to enhance light output efficiency, and toperform an image display with good display characteristics.

In the method of manufacturing a light-emitting apparatus as above in anembodiment, preferably, after a transparent electrode material isapplied so as to cover the opening portion and the electrode separationwall and hardened, the transparent electrode material is polished toexpose the surface of the electrode separation wall, thereby forming thetransparent electrode. When an ITO ink as the transparent electrodematerial is applied, hardened, and polished to form the transparentelectrode through the Damascene process, it is possible to increase thethickness of the transparent electrode up to about the electrodeseparation wall. Therefore, it is possible to easily cope with not onlythe positioning accuracy in the horizontal directions in a pixel butalso a positional stagger in the height direction generated in embeddingthe light-emitting device, and to easily secure electrical connectionbetween a transparent electrode layer and the contact metal.

In the method of manufacturing a light-emitting apparatus as above in anembodiment, the transparent electrode may be formed by jetting atransparent electrode material to the opening portion by an ink jettechnique and hardening the transparent electrode material. With aminute amount of the ITO ink as the transparent electrode materialapplied by the ink jet technique, it is possible also to preventlaminating a transparent electrode layer on the electrode separationwall by regulating the quantity of the ITO ink applied, and to easilyform the transparent electrode.

In the method of manufacturing a light-emitting apparatus as above in anembodiment, the transparent electrode may be formed by applying atransparent electrode material to the opening portion by screen printingand hardening the transparent electrode material. With the ITO ink asthe transparent electrode material applied by screen printing, thetransparent electrode can be formed easily.

In the method of manufacturing a light-emitting apparatus as above in anembodiment, preferably, a plurality of the light-emitting device mainbodies are transferred onto the resin portion, and the transparentelectrode is formed collectively so as to cover the contact metalsformed on the light output surfaces of a plurality of light-emittingdevices. With the plurality of contact metals covered collectively bythe transparent electrode, it is possible to secure electricalconnection between the wiring layer and the contact metals, and toenhance operating efficiency.

In the method of manufacturing a light-emitting apparatus as above in anembodiment, the wiring layer is preferably formed by forming a metalliclayer in the inside of the opening portion, and thereafter laminating anoble metal layer on the metallic layer. With the outermost surface ofthe wiring layer formed of a noble metal, it is possible to preventoxidation of the wiring layer in the region of contact with thetransparent electrode. This makes it possible to prevent the troublethat the wiring layer might be deteriorated due to corrosion with theresult of an increase in electric resistance thereof.

The method of manufacturing a light-emitting apparatus as above mayfurther include a step of forming a protective resin layer forprotecting the transparent electrode so as to cover the transparentelectrode in an embodiment. With the protective resin layer provided soas to cover the transparent electrode, it is possible to prevent thetransparent electrode from being deformed or deteriorated.

Further, the method of manufacturing a light-emitting apparatus as justmentioned may further include in an embodiment a step of forming adiffusion preventive layer for preventing mutual diffusion of acomponent of the protective resin layer and a component of thetransparent electrode, on the surface of the transparent electrode. Witha resin sheet as the diffusion preventive layer sandwiched between thetransparent electrode and the protective resin film, it is possible toprevent mutual diffusion of components between the transparent electrodeand the protective resin layer, and to prevent the conductivity of thetransparent electrode from being deteriorated.

In accordance with an eleventh aspect of the present invention in anembodiment, there is provided an image display apparatus including animage display surface formed by arranging a plurality of light-emittingapparatuses on an apparatus substrate, each of the light-emittingapparatuses including: a plurality of light-emitting devices each ofwhich includes a light-emitting device main body having a light outputsurface and transferred, and a contact metal formed on the light outputsurface; a wiring layer formed outside the regions of the light outputsurfaces; and a transparent electrode so formed as to cover the contactmetals and the wiring layer. With the transparent electrode so formed asto cover the contact metals and the wiring layer, electrical connectionbetween the contact metals and the wiring layer can be securelyachieved. In addition, since it is unnecessary to form the wiring layerin contact with the contact metals, it is possible to lower thepositioning accuracy in forming the wiring layer, as compared with thecase of forming a wiring layer in contact with the minute contactmetals, and thereby to enhance operating efficiency.

In accordance with a twelfth aspect of the present invention in anembodiment, there is provided a method of manufacturing an image displayapparatus including the steps of transferring a plurality oflight-emitting device main bodies each having a light output surfaceonto a resin portion so as to expose the light output surfaces, formingan electrode separation wall on the surface of the resin portion,providing the electrode separation wall with an opening portion largerin size than the light output surfaces so that the opening portionfronts on the light output surfaces, forming a wiring layer on thesurface of the resin portion in the inside of the opening portion, andforming a transparent electrode in the opening portion so that thetransparent electrode is connected directly to contact metals formed onthe light output surfaces and to the wiring layer.

As has been described above, according to the light-emitting device ofthe present invention in an embodiment, it is possible to obtain alight-emitting device in which an electrode is securely connected to alight-emitting device main body even where the light-emitting devicemain body is minute in size, without lowering the light outputefficiency of light generated in the light-emitting device main body.Namely, in the case of a minute light-emitting device, thelight-emitting device and an electrode can be securely connected to eachother by forming a transparent electrode larger as compared with thesize of the light-emitting device, without conducting accurate alignmentrelative to an electrode formation region such as a light output surfaceof the light-emitting device. Further, with such a transparentelectrode, even where the wide range of the light output surface iscovered directly by the electrode, light output efficiency can beenhanced as compared with the case of forming a metallic electrodeopaque to light.

In addition, by use of light-scattering conductive particulatescontained in the transparent electrode formed so as to cover the lightoutput surface in an embodiment, the light emitted from thelight-emitting device main body can be diffused to a wide range.Therefore, even if the light-emitting device is minute in size, thelight-emitting device can have a large apparent light emission surface.Further, with the transparent electrode formed of a material having arefractive index lower than the refractive index of the light-emittingdevice main body and with a resin layer lower in refractive index thanthe transparent electrode formed on the transparent electrode, lightoutput efficiency can be enhanced as compared with the case where theresin layer is formed directly on the light-emitting device main body.

Besides, the light-emitting apparatus according to the present inventionin an embodiment ensures that an electrode can be securely formed for aplurality of light-emitting devices. Further, also in the case where thelight-emitting apparatus is produced by arranging a plurality oflight-emitting devices, an electrode can be formed collectively, insteadof forming respective electrodes for the individual light-emittingdevices. Moreover, an electrode can be formed easily and securely evenin the case where the accuracy of alignment between the light-emittingdevices and the electrode is insufficient.

According to the method of manufacturing a light-emitting device of thepresent invention in an embodiment, even where the reduction in the sizeof the light-emitting device is advanced, the formation of a transparentelectrode so as to directly cover the whole area of the light outputsurface makes it possible to securely form the transparent electrode foreach of the light-emitting devices and to provide a light-emittingdevice having high reliability.

Furthermore, in the image display apparatus according to the presentinvention in an embodiment, even where pixels are formed by arranging amultiplicity of minute light-emitting devices, a transparent electrodeis securely formed without lowering the light output efficiency of eachdevice. Therefore, it is possible to provide an image display apparatushigh in image quality and reliability.

Besides, according to the method of manufacturing an image displayapparatus of the present invention in an embodiment, it is possible tosecurely form a transparent electrode for minute light-emitting devices,and to manufacture an image display apparatus on which the cost-basismerit arising from the manufacture of minute light-emitting devices andthe merit of an enhanced image quality are reflected sufficiently.

A transparent electrode is connected directly to light output surfacesso as to cover the whole areas of the light output surfaces. Thetransparent electrode is formed to be larger in area than the lightoutput surfaces, and are securely electrically connected to n-typesemiconductor layers including the light output surfaces. Namely, evenwhere the light-emitting diodes are minute in size, the n-typesemiconductor layers and the transparent electrode are securelyconnected to each other. As a result, the transparent electrode isformed for the light-emitting diodes more securely as compared to thecase where it is difficult to accurately form the transparent electrodesmaller in size than the light output surfaces in the light outputsurfaces, and the lights generated in the light-emitting diodes can beoutputted to the exterior of the devices without being shielded.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the following DetailedDescription of the Invention and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view showing the condition where alight-emitting device according to an embodiment of the presentinvention is disposed on a substrate.

FIG. 2 is a sectional view showing the condition where thelight-emitting device is disposed on the substrate according to anembodiment of the present invention.

FIG. 3 is a sectional view showing another example of the light-emittingdevice according to an embodiment of the present invention.

FIG. 4 is a sectional view showing the structure of a light-emittingapparatus according to the present invention.

FIGS. 5A to 5D are step diagrams showing the manufacturing steps of alight-emitting device according to an embodiment of the presentinvention, in which FIG. 5A is a diagram showing a step of disposing thelight-emitting device on a substrate, FIG. 5B is a diagram showing astep of forming a resist film, FIG. 5C is a diagram showing a step ofapplying an electrode paste, and FIG. 5D is a diagram showing a step offorming a transparent electrode.

FIGS. 6A to 6D are schematic diagrams showing a preferable method ofarranging light-emitting devices, which is suitable for a method ofmanufacturing an image display apparatus according to an embodiment ofthe present invention.

FIG. 7 is a sectional step diagram showing a first transfer step in themethod of manufacturing an image display apparatus according to anembodiment of the present invention.

FIG. 8 is a sectional step diagram showing an electrode pad forming stepin the manufacturing method according to an embodiment of the presentinvention.

FIG. 9 is a sectional step diagram showing an electrode pad forming stepafter the transfer onto a second temporary holding member in themanufacturing method according to an embodiment of the presentinvention.

FIG. 10 is a sectional step diagram showing an insulation layer formingstep in the manufacturing method according to an embodiment of thepresent invention.

FIG. 11 is a sectional step diagram showing a wiring forming step in themanufacturing method according to an embodiment of the presentinvention.

FIGS. 12A and 12B show the structure of a light-emitting apparatuscorresponding to one pixel in an image display apparatus according to asecond embodiment of the present invention, in which FIG. 12A is asectional view, and FIG. 12B is a plan view.

FIGS. 13A and 13B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where alignment marks are formed on an embedding substrate, inwhich FIG. 13A is a sectional view, and FIG. 13B is a plan view.

FIGS. 14A and 14B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where an embedding resin layer is formed, in which FIG. 14A isa sectional view, and FIG. 14B is a plan view.

FIGS. 15A and 15B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where the embedding resin layer is partially hardened to formseparation walls, in which FIG. 15A is a sectional view, and FIG. 15B isa plan view.

FIGS. 16A and 16B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thestep of selectively transferring light-emitting devices arranged on atransfer substrate onto a relay substrate, in which FIG. 16A is asectional view, and FIG. 16B is a plan view.

FIGS. 17A and 17B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thestep of embedding a light-emitting device into an embedding resin layer,in which FIG. 7A is a sectional view, and FIG. 17B is a plan view.

FIGS. 18A and 18B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thestep of hardening the embedding resin layer with the light-emittingdevice embedded therein to form device holding resin layers, in whichFIG. 18A is a sectional view, and FIG. 18B is a plan view.

FIGS. 19A and 19B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where red, green, and blue light-emitting devices are embeddedin one pixel, in which FIG. 19A is a sectional view, and FIG. 19B is aplan view.

FIGS. 20A and 20B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where electrode separation walls are formed on the deviceholding resin layers, in which FIG. 20A is a lateral sectional view, andFIG. 20B is a plan view.

FIGS. 21A and 21B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where a light emission side wiring layer is formed on thedevice holding resin layers, in which FIG. 21A is a lateral sectionalview, and FIG. 21B is a plan view.

FIGS. 22A and 22B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where a transparent electrode layer is formed so as to coverthe light emission side wiring layers and the electrode separationwalls, in which FIG. 22A is a lateral sectional view, and FIG. 22B is aplan view.

FIGS. 23A and 23B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where the electrode separation walls are exposed by polishingthe transparent electrode layer, in which FIG. 23A is a lateralsectional view, and FIG. 23B is a plan view.

FIGS. 24A and 24B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where a protective resin layer is formed on the transparentelectrode layer and the electrode separation walls, in which FIG. 24A isa lateral sectional view, and FIG. 24B is a plan view.

FIGS. 25A and 25B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thecondition where a display substrate is adhered, in which FIG. 25A is alateral sectional view, and FIG. 25B is a plan view.

FIGS. 26A and 26B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thestep of exfoliating the embedding substrate by laser ablation, in whichFIG. 26A is a sectional view, and FIG. 26B is a plan view.

FIGS. 27A and 27B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thestep of etching the device holding resin layer to expose bumps, in whichFIG. 27A is a sectional view, and FIG. 27B is a plan view.

FIGS. 28A and 28B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thestep of forming a back-side resin layer and vias, in which FIG. 28A is asectional view, and FIG. 28B is a plan view.

FIGS. 29A and 29B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thestep of opening a lead via outside the pixel region, in which FIG. 29Ais a sectional view, and FIG. 29B is a plan view.

FIGS. 30A and 30B illustrate a step in the method of manufacturing animage display apparatus according to the second embodiment, showing thestep of forming a wiring layer and a lead pad, in which FIG. 30A is asectional view, and FIG. 30B is a plan view.

DETAILED DESCRIPTION

The present invention relates to a light-emitting device, alight-emitting apparatus, an image display apparatus, a method ofmanufacturing a light-emitting device, and a method of manufacturing animage display apparatus. More particularly, the present inventionrelates to a light-emitting device, a light-emitting apparatus, an imagedisplay apparatus, a method of manufacturing a light-emitting device,and a method of manufacturing an image display apparatus in which lightemission efficiency is prevented from being lowered and an electrode isformed for minute light-emitting device main bodies with high accuracy.

Now, a light-emitting device, a light-emitting apparatus, an imagedisplay apparatus, a method of manufacturing a light-emitting device,and a method of manufacturing an image display apparatus according tothe present invention will be described below, referring to thedrawings.

FIRST EMBODIMENT

First, referring to FIGS. 1 and 2, an example of the light-emittingdevice according to the present invention will be described. While alight-emitting diode will be taken as an example of the light-emittingdevice in the description of this example, the light-emitting deviceaccording to the present invention is not limited to the light-emittingdiode. FIG. 1 is a perspective view showing the condition where alight-emitting diode 1 is disposed on a substrate 2, and FIG. 2 is asectional view showing the condition where the light-emitting diode 1 isdisposed on the substrate 2.

As shown in FIGS. 1 and 2, the light-emitting diode 1 is disposed in thestate of being fixed to an insulation resin layer 3 formed on thesubstrate 2, and a transparent electrode 4 is formed directly so as tocover a light output surface 5.

The light-emitting diode 1 is so disposed that an n-type semiconductorlayer 6 made to be of the n-type conduction type by doping with animpurity is fixed to the insulation resin layer 3 so as to be exposedfrom the insulation resin layer 3. The insulation resin layer 3 isformed on the substrate 2, on which a wiring 7 to be connected to thelight-emitting diode 1 has previously been formed, and thelight-emitting diode 1 is fixedly disposed so as to be connected to thewiring 7. In forming the insulation resin layer 3 after fixinglydisposing the light-emitting diode 1 onto the substrate 2, it sufficesto remove the insulation resin layer 3 so as to expose the n-typesemiconductor layer 6, by etching or the like. While the substrate 2 inthis example is an apparatus substrate of an image display apparatusformed by arranging the light-emitting diodes 1, the substrate 2 may bea transfer substrate for temporary transfer of the light-emittingdiode(s) 1. The top surface of the n-type semiconductor layer 6 exposedfrom the insulation resin layer 3 of the light-emitting diode 1 is madeto be the light output surface 5, and light generated in thelight-emitting diode 1 is emitted to the upper side in the figures.

The light-emitting diode 1 is in the form of a chip, and is made to be ahomo-type light-emitting diode or a hetero-type light-emitting diode inwhich an n-type semiconductor layer and a p-type semiconductor layer arelaminated. In this case, the light-emitting diode 1 is not limited to alight-emitting diode having the structure in this example, and may be alight-emitting diode formed by selecting a desired device structure andmaterials so that it can respectively emit light with one of variouswavelengths such as blue, green, yellow, red, infrared, etc. Besides,the light-emitting diode 1 may be a light-emitting diode enhanced inlight emission efficiency by forming a double hetero structure orquantum well structure in which an active layer is sandwiched between ap-type clad layer and an n-type clad layer. While the light-emittingdiode 1 in this example is a light-emitting diode roughly flatplate-like in shape, the light-emitting diode may be a light-emittingdiode in which the lamination direction of the semiconductor layer isinclined against the major surface of the device forming substrate. Forexample, the shape of the light-emitting diode is not limited to theroughly flat plate-like shape, and may have any device shape such as thesectional shape of the device is tapered and the outside shape of thedevice is a hexagonal pyramid. Furthermore, the light-emitting deviceaccording to the present invention is not limited to the light-emittingdiode, and may be such a light-emitting device as a semiconductor laserdevice.

The transparent electrode 4 is connected directly to the light outputsurface 5 so as to cover the whole area of the light output surface 5.Further, the transparent electrode 4 is formed to be larger in size thanthe light output surface 5, and is securely electrically connected tothe n-type semiconductor layer 6 including the light output surface 5.Namely, even where the light-emitting diode 1 is minute in size, assuredconnection between the n-type semiconductor layer 6 and the transparentelectrode 4 is achieved. Therefore, electrical connection between then-type semiconductor layer 6 and the transparent electrode 4 can beperformed securely, as compared with the case where it is difficult forthe transparent electrode smaller in size than the light output surface5 to be accurately formed in the region of the light output surface 5.In addition, since the transparent electrode 4 is larger in size thanthe light output surface 5, even in the case where the position of thetransparent electrode 4 is staggered from the position of thelight-emitting diode 1, the electrical connection between thelight-emitting diode 1 and the transparent electrode 4 is attainedinasmuch as the light-emitting diode 1 is disposed in the region wherethe transparent electrode 4 is formed.

Besides, the transparent electrode 4 is formed to be greater in sizethan the light output surface 5, thereby providing direct connectionbetween a wiring 8 formed on the surface of the insulation resin layer 3and the light-emitting diode 1. Therefore, a device main body of thelight-emitting diode 1 and the wiring 8 can be connected to each otherwithout performing an intricate step, as contrasted to the case where anelectrode is formed on the light output surface 5, and Further, theelectrode and the wiring 8 are connected to each other through aconnection wire. Particularly, as the light-emitting diode 1 becomesminuter in size, it becomes more difficult to form the electrode and theconnection wire in predetermined regions in predetermined sizes. In viewof this, according to the transparent electrode 4 formed as in thisexample, the light-emitting diode 1 and the wiring 8 can be easilyconnected without any restriction by the size of the light-emittingdiode 1.

Further, as an example, the transparent electrode 4 is formed by coatingthe whole area of the light output surface 5 with a paste containingconductive particulates dispersed in a light-transmitting resin. Theconductive particulates are formed, for example, of a light-transmittingand conductive material such as Indium Tin Oxide (ITO), and those whichare in a needle shape promising easy scattering of light can be used.When such a transparent electrode 4 is used, the transparent electrode 4can be connected not only to the light output surface 5 but also to sidesurfaces 9 of the n-type semiconductor layer 6, in the case where thelight-emitting diode 1 is so disposed that the n-type semiconductorlayer 6 protrudes from the insulation resin layer 3 as in this example.Further, the light going from the light-emitting diode 1 into thetransparent electrode 4 can be scattered by the conductive particulates,thereby emitting the light while diffusing the light to a wide range inthe exterior of the device. Thus, with the conductive particulatescontained in the transparent electrode 4, the light-emitting diode 1 canhave an apparent light emission area larger than the actual sizethereof, so that a light-emitting device preferable for use in alight-emitting apparatus or an image display apparatus can be obtainedeven where the light-emitting diode is minute in size.

In addition, where the n-type semiconductor layer 6 protrudes from theinsulation resin layer 3 as in this example, both the light outputsurface 5 and the side surfaces 9 are connected to the transparentelectrode 4, so that it is possible to secure a large area of contactbetween the transparent electrode 4 and the light-emitting diode 1.Particularly, as the size of the light-emitting diode 1 becomes a minutesize of about several tens of micrometers, the ratio of the area of theside surfaces 9 to the area of the n-type semiconductor layer 6 to beconnected to the transparent electrode 4 increases. Therefore, if theconnection to the transparent electrode 4 can be secured through theside surfaces 9, the electric resistance in the connection region can bereduced, and the light-emitting diode 1 can be made to be alight-emitting device with high reliability. Besides, a contact layerformed of a metallic material such as Ti may be preliminarily formed onthe side surfaces 9. With such a contact layer, it is possible toenhance the performance of contact between the n-type semiconductorlayer 6 and the transparent electrode 4, and the light-emitting diode 1can be made to be a light-emitting device with a further higherreliability.

The p-type semiconductor layer 10 is connected to the wiring 7, which isformed on the surface of the substrate 2 and so disposed on thesubstrate 2 as to be covered by the insulation resin layer 3. While thep-type semiconductor layer 10 is connected directly to the wiring 7 inthis example, the n-type semiconductor layer 6 may be connected to thewiring 7. In that case, the transparent electrode 4 is formed on thewhole area of the p-type semiconductor layer 10, and the top face of thep-type semiconductor layer 10 constitutes the light output surface.

Next, referring to FIG. 3, another example of the light-emitting deviceaccording to an embodiment of the present invention will be described.The light-emitting device in this example is a light-emitting diode 19having a device structure similar to that of the light-emitting diodedescribed above referring to FIGS. 1 and 2. A p-type semiconductor layer21 is connected to a wiring 16 formed on a substrate 15. A transparentelectrode 18 is formed of a material having a refractive index lowerthan that of an n-type semiconductor layer 20 having a light outputsurface 22. Such a transparent electrode 18 can be formed of alight-transmitting material by a film forming method such as sputteringand vacuum vapor deposition. For example, where the light-emitting diode19 is composed of a GaN-based semiconductor, the n-type semiconductorlayer 20 has a refractive index of about 2.4, whereas an ITO filmconstituting a bulk with a refractive index of about 2.0 is formed asthe transparent electrode 18 directly on the light output surface 22.Further, a resin layer 23 having a refractive index of about 1.5 to 1.6can be formed on the upper side of the transparent electrode 18 as anovercoat layer of the light-emitting diode 19. Therefore, where thelight-emitting diode 19 is made to emit light in air whose refractiveindex is about 1.0, the transparent electrode 18 has a refractive indexbetween the refractive index of the light-emitting diode 19 and therefractive index of the resin layer 23 covering the light-emitting diode19, whereby the light reflected at the interface between the lightoutput surface 22 and the resin layer 23 can be reduced, as compared tothe case where a resin layer is formed directly on the light outputsurface 22. Therefore, it is possible to enhance light emissionefficiency to the exterior of the device. In addition, by coating thewhole area of the light output surface with a paste containing ITOparticulates dispersed in a light-transmitting resin, it is possible toform a transparent electrode whose refractive index is lower than therefractive index of the device main body of the light-emitting diode 19and higher than the refractive index of the resin layer 23. In such atransparent electrode, the light output efficiency can be furtherenhanced by, for example, admixing the resin with titanium oxideparticulates whose refractive index is higher than the refractive indexof the GaN-based semiconductor layer.

Next, an example of the light-emitting apparatus according to anembodiment of the present invention will be described. FIG. 4 is asectional view showing the configuration of the light-emitting apparatusaccording to this example. As shown in FIG. 4, the light-emittingapparatus 25 includes light-emitting diodes 28R, 28G, 28B disposed at apredetermined device interval in an insulation resin layer 27 formed ona substrate 26. The light-emitting diodes 28R, 28G, 28B are respectivelya red light-emitting diode, a green light-emitting diode, and a bluelight-emitting diode, which emit light in three primary colors,respectively. These light-emitting diodes are provided as a set, toconstitute the light-emitting apparatus 25. The light-emitting diodes28R, 28G, 28B are formed in a size of about 10 μm square, for example.The surfaces, exposed from the insulation resin layer 27, of thelight-emitting diodes 28R, 28G, 28B are made to be light output surfacesof the light-emitting diodes, and a transparent electrode 29 is directlyformed so as to cover the whole areas of the light output surfaces.Specifically, by forming the transparent electrode 29 in a size of about100 μm square, it is possible to directly cover the whole part of theregion where the light-emitting diodes 28R, 28G, 28B are disposed, evenwhere the device interval is sufficiently large. Therefore, thetransparent electrode 29 is formed collectively, instead of formingelectrodes individually for the minute light-emitting devices of about20 μm square in size. With the transparent electrode 29 thus formed in asize larger than the device size of the light-emitting diodes 28R, 28G,28B, i.e., the size of the light output surfaces of the devices, it ispossible to easily connect the transparent electrode to the light outputsurface of each device inasmuch as each device is disposed in the regionwhere the transparent electrode 29 is formed. Besides, in this example,the transparent electrode 29 is formed collectively on the light outputsurfaces of the light-emitting diodes 28R, 28G, 28B so as to constitutea common electrode in driving each of the light-emitting diodes. Inaddition, the respective devices are individually driven by electricpower supplied through wirings separately connected to thelight-emitting diodes 28R, 28G, 28B.

The transparent electrode 29 is formed from a light-transmittingconductive material such as ITO by a film forming method such assputtering and vacuum vapor deposition; more preferably, the transparentelectrode 29 may be formed by applying an electrode paste containingconductive particulates dispersed in a light-transmitting resin. By useof such a transparent electrode containing the conductive particulates,the light emitted from the light-emitting diodes 28R, 28G, 28B can beemitted while being diffused from a light emission surface 30 of thelight-emitting apparatus 25. Therefore, according to the light-emittingapparatus 25 of this example, the light emission surface 30 can be alight emission surface with a large apparent light emission surface.According to such a light-emitting apparatus 25, the light in red,green, and blue colors can be emitted to a wide range, whereby it ispossible to configure a light-emitting apparatus having a large apparentlight emission surface, as compared with the actual size of thelight-emitting diodes 28R, 28G, 28B, and a sufficient luminance.

Next, referring to FIGS. 5A to 5D, a method of manufacturing alight-emitting device according to the present invention will bedescribed, taking the light-emitting diode as an example. First, asshown in FIG. 5A, a wiring 32 is formed on a substrate 31, and alight-emitting diode 34 is transferred onto the substrate 31 so that ap-type semiconductor layer 34 b is connected to the wiring 32. Further,an insulation resin layer 33 is formed so as to cover the substrate 31,the wiring 32, and the light-emitting diode 34. The insulation resinlayer 33 is selectively removed so as to expose a light output surface34 c of the light-emitting diode 34 from the insulation resin layer 33.The selective removal of the insulation resin layer 33 can be conducted,for example, by sandblasting, ashing, or the like. Furthermore, theinsulation resin layer 33 may be so removed as to expose the sidesurfaces of an n-type semiconductor layer 34 a including the lightoutput surface 34 c of the light-emitting diode 34. In addition, awiring 35 to be connected to the light-emitting diode 34 in the latterstep for driving the light-emitting diode 34 is preliminarily formed onthe surface of the insulation resin layer 33 after the selective removalof the insulation resin.

Subsequently, as shown in FIG. 5B, an electrode pattern is formed. Aresist film 36 is formed so as to cover both the surface of theinsulation resin layer 33 after the selective removal of the insulationresin and the light-emitting diode 34 exposed from the insulation resinlayer 33. For example, a photoresist film as the resist film is formed,followed by exposure and development, whereby an opening portion 36 adefining the shape of the electrode pattern is formed. The openingportion 36 a is formed by removing the resist film 36 so as to exposethe whole part of the light output surface 34 c of the light-emittingdiode 34. Besides, in this example, the opening portion 36 a is soformed as to expose also the wiring 35.

Subsequently, as shown in FIG. 5C, an electrode paste is applied intothe opening portion 36 a and onto the surface of the resist film 36, toform a transparent electrode layer 37. As the electrode paste forforming the transparent electrode layer 37, a paste containingconductive particulates dispersed in a light-transmitting resin can beused. Besides, the electrode forming material is not limited to theelectrode paste used in this example; for example, a resin, which isconductive by itself, may be used as the material. The electrode pasteis applied to the light output surface 34 c of the light-emitting diode34 and the wiring 35, which front on the opening portion 36 a, so thatthe light output surface 34 c and the wiring 35 are connected to eachother collectively through the transparent electrode layer 37.

Furthermore, as shown in FIG. 5D, the transparent electrode layer 37formed on the resist film 36 is removed, to leave the transparentelectrode 38 only in the opening portion 36 a. The transparent electrodelayer 37 formed on the surface of the resist film 36 can be removed, forexample, by a removing method such as polishing by use of fixed abrasivegrains or free abrasive grains, sandblasting, ashing, etc. By formingthe transparent electrode 38 in this manner, the transparent electrode38 is connected also to the side surfaces of the light-emitting diode 34protruding from the insulation resin layer 33, whereby the connectionbetween the light-emitting diode 34 and the transparent electrode 38 canbe securely achieved.

Particularly, in the case where a step is generated between the surfaceof the insulation resin layer 33 and the light output surface 34 c ofthe light-emitting diode 34 protruding from the insulation resin layer33, the formation of the transparent electrode 38 in the above-mentionedmanner makes it possible to enhance the performance of contact betweenthe transparent electrode 38 and the light-emitting diode 34, ascompared with the case of forming an electrode film from a transparentelectrode material such as ITO by sputtering or vacuum vapor deposition.

Further, according to the method of manufacturing a light-emittingdevice of the present invention in an embodiment, the transparentelectrode 38 is formed on the light output surface 34 c of thelight-emitting diode 34, whereby the transparent electrode 38 can besecurely connected to the light output surface 34 c even where thelight-emitting diode 34 is a minute light-emitting device with a size ofabout 10 μm square, and the light output efficiency to the exterior ofthe device is little lowered. Namely, with the opening portion 36 aformed to be larger in size than the light output surface 34 c of thelight-emitting diode 34, the transparent electrode 38 formed in themanner of filling the opening portion 36 a and the light output surface34 c are securely connected to each other. Besides, the method ofmanufacturing a light-emitting device according to the present inventionis not limited to that in this example; the electrode paste may also beapplied directly to the light output surface of the light-emittingdevice by a screen printing method using a screen mask provided with anelectrode pattern. Incidentally, the method of manufacturing alight-emitting device according to the present invention is preferablealso in the case of manufacturing a light-emitting device withoutperforming a transferring step.

Next, an image display apparatus and a method of manufacturing the sameaccording to the present invention will be described. In the following,a method of transferring light-emitting devices will be described first,and then the image display apparatus and the method of manufacturing thesame will be described in detail. The method of transferringlight-emitting devices according to this example reside in conducting atwo-stage pitch-enlarging transfer in which light-emitting devicesformed on a first substrate in a high integration degree are transferredonto a temporary holding member so that they are spaced wider apart fromeach other than they have been on the first substrate, and then thelight-emitting devices held on the temporary holding member aretransferred onto a second substrate so that they are spaced furtherwider apart from each other. Incidentally, while the transfer isperformed in two stages in this example, a three- or more-stage transfermay also be adopted according to the desired degree of enlargement ofdevice interval.

FIGS. 6A to 6D illustrate basic steps of the two-stage pitch-enlargingtransfer method. First, light-emitting devices 40, for example, aredensely formed on a first substrate 39 a shown in FIG. 6A. By formingthe light-emitting devices densely, it is possible to increase thenumber of the devices produced per substrate, and to lower the productcost. The first substrate 39 a is any of various device formingsubstrates such as a semiconductor wafer, a glass substrate, a quartzglass substrate, a sapphire substrate, a plastic substrate, etc., andthe light-emitting devices 40 may be formed directly on the firstsubstrate 39 a or may be arranged on the first substrate 39 a afterbeing formed on another substrate.

Next, as shown in FIG. 6B, the light-emitting devices 40 are transferredfrom the first substrate 39 a onto a first temporary holding member 39b, and are held on the first temporary holding member 39 b, which isshown by a broken line. In this instance, the light-emitting devices 40are spaced wider apart from each other and arranged in a matrix patternas shown in the figure. Namely, the light-emitting devices 40 are sotransferred that they are spaced wider apart in x-direction and arespaced wider apart in y-direction perpendicular to the x-direction. Thedevice interval after the wider spacing is not particularly limited, andmay be, for example, an interval determined taking into account theformation of a resin portion and/or the formation of electrode pads inthe subsequent step. At the time of transfer from the first substrate 39a onto the first temporary holding member 39 b, all of thelight-emitting devices 40 on the first substrate 39 a may be transferredso that they are spaced wider apart from each other. In this case, thesize of the first temporary holding member 39 b must only be not lessthan the size obtained by multiplying the number (in x-direction andy-direction, respectively) of the light-emitting devices 40 arranged inthe matrix pattern by the enlarged interval. Also, some of thelight-emitting devices 40 on the first substrate 39 a may be transferredonto the first temporary holding member 39 b while being spaced widerapart from each other.

After the first transfer step above-described, as shown in FIG. 6C, thelight-emitting devices 40 present on the first temporary holding member39 b are spaced apart from each other. In view of this, the covering ofthe surroundings of the device with a resin and the formation of anelectrode pad are performed on the basis of each light-emitting device40. The covering of the surroundings of the devices with the resin isformed for facilitating the formation of the electrode pads, forfacilitating the handling of the devices in the subsequent secondtransfer step, and the like purposes. The formation of the electrodepads is conducted after the second transfer step followed by the finalwiring, as will be described later. Therefore, the electrode pads areformed in a comparatively large size in order to obviate defectivewiring. Incidentally, the electrode pads are not shown in FIG. 6C. Bycovering the surroundings of each light-emitting device 40 with a resin40 a, a resin-potted chip 40 b is formed. The light-emitting device 40is located roughly in the center of the resin-potted chip 40 b. However,the light-emitting device 40 may be located at a position deviated fromthe center toward one side or one corner of the resin-potted chip 40 b.Also in that case, an electrode can be securely connected to thelight-emitting device 40 by forming a larger electrode pad as comparedwith the light-emitting device 40.

Next, as shown in FIG. 6D, the second transfer step is carried out. Inthe second transfer step, the light-emitting devices 40 arranged in thematrix pattern on the first temporary holding member 39 b aretransferred onto a second substrate 39 c so that the devices 40 arespaced further apart from each other on the basis of the resin-pottedchips 40 b.

In the second transfer step, also, the adjacent light-emitting devices40 are spaced wider apart from each other on the basis of theresin-potted chips 40 b, and are arranged in a matrix pattern as shownin the figure. Namely, the light-emitting devices 40 are transferredwhile being spaced wider apart from each other in x-direction and iny-direction perpendicular to the x-direction. Assuming that thepositions of the devices arranged by the second transfer step correspondto the pixels in a final product such as an image display apparatus, theproduct obtained by multiplying the original pitch of the light-emittingdevices 40 by a roughly integral number is the pitch of thelight-emitting devices 40 arranged through the second transfer step.Here, let the magnification factor of the pitch of the light-emittingdevices 40 attendant on the transfer from the first substrate 39 a ontothe first temporary holding member 39 b be n and let the magnificationfactor of the pitch of the light-emitting devices 40 attendant on thetransfer from the first temporary holding member 39 b onto the secondsubstrate 39 c be m, then the value E of the roughly integral number isrepresented as E=n×m. Wiring is applied to each of thelight-transmitting devices 40 spaced wider apart from each other on thebasis of the resin-potted chips 40 b on the second substrate 39 c. Inthis case, in order to restrain defective connection as securely aspossible, the wiring is conducted by utilizing the previously formedelectrode pads and the like. Where the light-emitting devices 40 arelight-emitting diodes or the like, for example, the wiring includes thewirings to p-electrode and n-electrode.

In the two-stage pitch-enlarging transfer method shown in FIGS. 6A to6D, the formation of the electrode pads and the potting with a resin canbe performed by utilizing the enlarged spaces after the first transfer,and the wiring is conducted after the second transfer. In this case, thewiring is carried out while restraining defective connection as securelyas possible, by utilizing the previously formed electrode pads and thelike. Therefore, it is possible to enhance the yield of the imagedisplay apparatus. In addition, in the two-stage pitch-enlargingtransfer method, there are two steps of enlarging the pitch of thedevices, and, by performing the pitch-enlarging transfer in a pluralityof steps for spacing the devices wider apart from each other, the numberof transferring steps is reduced in practice. Namely, for example, letthe magnification factor of the pitch attendant on the transfer from thefirst substrate 39 a onto the first temporary holding member 39 b be 2(n=2) and let the magnification factor of the pitch attendant on thetransfer from the first temporary holding member 39 b onto the secondsubstrate 39 c be 2 (m=2), and if the pitch-enlarging transfer should becarried out in a single step, the final magnification factor would be2×2=4, and there would be need for conducting transfer 16 (=42) times,i.e., conducting alignment of the first substrate 16 times. On the otherhand, in the two-stage pitch-enlarging transfer method according to thisexample, the number of times of alignment needed is only 8, i.e., thesimple sum of 4 (the square of the magnification factor of 2 in thefirst transfer step) and 4 (the square of the magnification factor of 2in the second transfer step). In other words, since (n+m)2=n2+2 nm+m2,in the case of intending the same pitch magnification factor upontransfer, the two-stage pitch-enlarging transfer method according tothis example will necessarily reduce the number of times of transfer by2 nm, as compared with the single-stage pitch-enlarging transfer method.This promises reductions in the time and cost of the manufacturingsteps, by amounts corresponding to 2 nm times of transfer, and isparticularly profitable where the magnification factor is large.

In the second transfer step as above, the light-emitting devices 40 aretransferred from the temporary holding member 39 b onto the secondsubstrate 39 c while being handled as the resin-potted chips 40 b. Byconfiguring such resin-potted chips 40 b, the surroundings of thelight-emitting devices 40 are flattened by the resin 40 a, so that thelight-emitting devices 40 and the electrode pads can be securelyconnected to each other by forming the electrode pads larger in sizethan the light-emitting devices 40, even where the size of thelight-emitting devices 40 are as minute as about 10 μm, for example. Aswill be described later, the final wiring is conducted after the secondtransfer step. Therefore, defective wiring can be prevented byconducting the wiring by utilizing the electrode pads, which arecomparatively large in size.

Next, referring to FIGS. 7 to 11, an image display apparatus and amethod of manufacturing an image display apparatus according to thepresent invention will be described. In this example, a GaN-basedlight-emitting diode in the shape of a hexagonal pyramid is used as anexample of the light-emitting device.

First, as shown in FIG. 7, a plurality of light-emitting diodes 42 areformed in a matrix pattern on a major surface of a first substrate 41.The light-emitting diodes 42 may be about 10 μm in size. As aconstituent material of the first substrate 41, there is used a materialhaving a high transmittance for the wavelength of laser with which thelight-emitting diodes 42 are irradiated, such as a sapphire substrate.For each of the light-emitting diodes 42, components up to p-electrodeor the like have been formed, but the final wiring has not yet beenformed. Grooves 42 g for separation between the devices have beenformed, so that the individual light-emitting diodes 42 can beseparated. The grooves 42 g are formed, for example, by reactive ionetching. Such a first substrate 41 is opposed to the first temporaryholding member 43, and selective transfer is conducted, as shown in FIG.8.

A release layer 44 and an adhesive layer 45 in two layers are formed onthe surface, opposed to the first substrate 41, of the first temporaryholding member 43. As the first temporary holding member 43, forexample, a glass substrate, a quartz glass substrate, a plasticsubstrate, or the like may be used. Examples of the material of therelease layer 44 on the first temporary holding member 43 include afluororesin coat, a silicone resin, a water-soluble adhesive, forexample, polyvinyl alcohol (PVA), a polyimide and the like. As theadhesive layer 45 on the first temporary holding member 43, a layer ofany of ultraviolet ray (UV)-curable adhesives, thermosetting adhesives,thermoplastic adhesives and the like may be used. As one example, aquartz glass substrate is used as the first temporary holding member 43,a polyimide film 4 μm in thickness is formed as the release layer 44,and thereafter a UV-curable adhesive as the adhesive layer 45 is appliedin a thickness of about 20 μm.

The adhesive layer 45 on the first temporary holding member 43 is soconditioned that cured regions 45 s and uncured regions 45 y are mixedlypresent, and is so registered that the light-emitting diodes 42 to beselectively transferred are located in the uncured regions 45 y. Theconditioning for ensuring that the cured regions 45 s and the uncuredregions 45 y are mixedly present may be conducted, for example, by amethod in which the UV-curable adhesive is selectively irradiated withUV rays at a pitch of 200 μm by use of an exposure apparatus so that theadhesive is uncured in the regions of transfer of the light-emittingdiodes 42 and is cured in the other regions. After such an alignment,the light-emitting diodes 42 at the intended transfer positions areirradiated with laser from the back side of the first substrate 41, andthese light-emitting diodes 42 are exfoliated from the first substrate41 through laser ablation. The GaN-based light-emitting diodes 42 can beexfoliated comparatively easily, since GaN decomposes into metallic Gaand nitrogen at the interface between itself and sapphire. Examples ofthe laser for irradiation therewith include excimer laser andhigh-harmonic YAG laser.

By the exfoliation utilizing laser ablation, the light-emitting diodes42 relevant to the selective irradiation are decomposed at the interfacebetween the GaN layer and the first substrate 41, and are transferred inthe manner that p-electrode portions thereof pierces into the adhesivelayer 45 on the other side. As for the other light-emitting diodes 42,which are not irradiated with the laser, the corresponding portions ofthe adhesive layer 45 are the cured regions 45 s, and they are notirradiated with the laser, so that the light-emitting diodes 42 are nottransferred to the side of the first temporary holding member 43.Incidentally, while only one light-emitting diode 42 is selectivelyirradiated with laser in FIG. 7, the light-emitting diodes 42 located inthe regions spaced apart from the one light-emitting diode 42 by npitches are also irradiated with the laser in the same manner. By such aselective transfer, the light-emitting diodes 42 are arranged on thefirst temporary holding member 43 at a pitch greater than the pitch onthe first substrate 41.

In the condition where the light-emitting diodes 42 are held by theadhesive layer 45 on the first temporary holding member 43, the backside of each light-emitting diode 42 is the n-electrode side (cathodeside), and the back side of the light-emitting diode 42 has beendeprived of the resin (adhesive) by removal and cleaning. Therefore,when an electrode pad 46 is formed as shown in FIG. 8, the electrode pad46 is electrically connected to the back side of the light-emittingdiode 42. The back side of the light-emitting diode 42 is made to be alight output surface of the light-emitting diode 42, and the electrodepad 46 is directly formed so as to cover the whole area of the lightoutput surface. In this case, the electrode pad on the cathode side maybe about 60 μm square in size. The electrode pad 46 is formed byapplying an electrode paste containing conductive particulates dispersedin a light-transmitting resin. Therefore, light emission is not hinderedeven if the back side of the light-emitting diode 42 is covered by theelectrode in a large area, so that a large electrode can be formed.Accordingly, even where the size of the light-emitting diode 42 is about10 μm square as in this example, the electrode can be formed easily.

FIG. 9 shows the condition where the light-emitting diodes 42 have beentransferred from the first temporary holding member 43 onto a secondtemporary holding member 47, via holes 50 on the anode (p-electrode)side have been formed, thereafter anode-side electrode pads 49 have beenformed, and the adhesive layer 45 composed of the resin has been diced.As a result of the dicing, device separation grooves 51 are formed, sothat the light-emitting diodes 42 are sectioned on a device basis. Thedevice separation grooves 51, for separation of the light-emittingdiodes 42 arranged in a matrix pattern, are composed of pluralities ofparallel lines extending in row and column directions in a flat surfacepattern. At bottom portions of the device separation grooves 51, thesurface of the second temporary holding member 47 is exposed.

In addition, a release layer 48 is formed on the second temporaryholding member 47. The release layer 48 can be formed, for example, byusing a fluororesin coat, a silicone resin, a water-soluble adhesive(for example, PVA), a polyimide, or the like. As an example of thesecond temporary holding member 47, there can be adopted a so-calleddicing sheet, which is composed of a plastic substrate coated with aUV-curable pressure sensitive adhesive and of which the tack is loweredupon irradiation with UV rays.

In conducting the transfer from the first temporary holding member 43onto the second temporary holding member 47, the release layer 44 formedon the temporary holding member 43 is irradiated with excimer laser fromthe back side of the temporary holding member 43. Where the releaselayer 44 is formed of a polyimide, for example, the irradiation causesexfoliation at the interface between the polyimide and the quartzsubstrate through ablation of the polyimide, and each light-emittingdiode 42 is transferred to the side of the secondary temporary holdingmember 47. In addition, in forming the anode-side electrode pads 49, theface side of the adhesive layer 45 is etched by oxygen plasma until thesurfaces of the light-emitting diodes 42 are exposed. First, via holes50 can be formed by use of excimer laser, high-harmonic YAG laser, orcarbon dioxide laser. In this case, the via holes 50 each have adiameter of about 3 to 7 μm. The anode-side electrode pads 49 are formedof Ni/Pt/Au or the like. The dicing process is conducted by dicing usingan ordinary blade, or is conducted by use of the above-mentioned laserwhere narrow cuts of not more than 20 μm in width are needed. The widthof the cuts depends on the size of the light-emitting diodes 42 coveredby the adhesive layer 45 formed of the resin in the pixel of the imagedisplay apparatus.

FIG. 10 shows the condition where light-emitting diodes 42, 61, 62 forthree colors of RGB have been arranged on a second substrate 60 and beencoated with an insulation layer 59. When the light-emitting diodes 42,61, 62 are mounted on the second substrate 60 at staggered colorpositions by the above-described transfer method, pixels composed ofthree colors can be formed, with the pixel pitch left unchanged.Examples of the material of the insulation layer 59 include transparentepoxy adhesives, UV-curable adhesives, polyimides, etc. Thelight-emitting diodes 42, 61, 62 for three colors may not necessary havethe same shape. In FIG. 10, the red light-emitting diode 61 has astructure lacking the hexagonal pyramidal GaN layer, and is different inshape from other light-emitting diodes 42 and 62. In this stage,however, the light-emitting diodes 42, 61, 62 have already been coveredby the resin-based adhesive to form resin-potted chips, so that thelight-emitting diodes 42, 61, 62 can be handled in the same manneralthough they differ in device structure.

FIG. 11 illustrates a step of forming wirings. In the figure, theinsulation layer 59 have been provided with opening portions 65, 66, 67,68, 69, 70, and wirings 63, 64, 71 for connection between the anode andcathode electrode pads of the light-emitting diodes 42, 61, 62 and anelectrode layer 57 for wiring of the second substrate 60 have beenformed. In this case, the opening portions, or via holes, can be largein shape because the areas of the electrode pads 46, 49 of thelight-emitting diodes 42, 61, 62 are large, and the positional accuracyof the via holes can be rough, as compared with that of via holes formeddirectly in each light-emitting diode. The via holes may be about φ20 μmin diameter, for the electrode pads 46, 49 of about 60 μm square insize. In addition, the depths of the via holes are of three kinds, onefor connection to the wiring substrate, one for connection to the anode,and one for connection to the cathode. Therefore, the opening portionsare formed in optimal depths by controlling the number of pulses oflaser. Thereafter, a protective layer is formed on the wirings, tocomplete a panel of the image display apparatus. In this case, theprotective layer may be formed by use of a material such as atransparent epoxy adhesive, in the same manner as the insulation layer59 shown in FIG. 11. The protective layer is hardened by heating, tocompletely cover the wirings. Thereafter, the wiring at a panel endportion is connected to a driver IC, to manufacture a drive panel,thereby completing the image display apparatus.

According to the method of manufacturing an image display apparatus inthis example, the device interval has already been enlarged when thelight-emitting diodes 42 are held on the first temporary holding member43, so that electrode pads 46, 49 and the like comparatively large insize can be provided by utilizing the enlarged interval. Since wiring isconducted by utilizing the comparatively large electrode pads 46 and 49,the wirings can be easily formed even where the final apparatus size isextremely large as compared with the device size. In addition, in themethod of manufacturing an image display apparatus according to thisexample, the surroundings of the light-emitting devices are flattened bycoating with the adhesive layer 45, so that the electrode pads 46 and 49can be formed with good accuracy. Furthermore, with the electrode pad 46formed to be larger in size than the light output surface of thelight-emitting diode 42, the light-emitting diode 42 can be securelyconnected to the electrode even where the light-emitting diode 42 isminute in size. Besides, with the electrode provided as a transparentelectrode, it is possible to manufacture an image display apparatus withhigh image quality, without lowering the light output efficiency.

SECOND EMBODIMENT

Next, as an embodiment of the present invention, an example in whichelectrodes are formed at parts of light output surfaces oflight-emitting devices and a transparent electrode is formed so as tocover the whole areas of the light output surfaces will be described.This embodiment differs from the above-described first embodiment inthat contact metals are formed on the light output surfaces of thelight-emitting devices and that light emission side wiring layers areformed outside the regions of the light output surfaces. Now, alight-emitting apparatus, an image display apparatus, a method ofmanufacturing a light-emitting apparatus, and a method of manufacturingan image display apparatus according to the present invention will bedescribed in detail below, referring to the drawings.

FIGS. 12A and 12B schematically illustrate the structure of alight-emitting device corresponding to one pixel in an image displayapparatus formed by arranging the light-emitting devices according tothis embodiment, in which FIG. 12A is a sectional view, and FIG. 12B isa plan view. The image display apparatus is configured by arranging aplurality of the light-emitting apparatuses, each of which correspondsto one pixel. As shown in FIG. 12A, the light-emitting apparatus and theimage display apparatus according to this embodiment have a structure inwhich an adhesive layer 101 and a protective resin layer 102 are formedon a display substrate 100, a transparent electrode layer 103 is formedon the protective resin layer 102, and the transparent electrode layer103 is connected to light output surfaces 105 a of light-emittingdevices 105R, 105G, 105B. FIG. 12A is a sectional view of the imagedisplay apparatus shown in FIG. 12B, taken along the broken line in FIG.12B. Contact metals 104R, 104G, 104B are formed respectively on thelight output surfaces 105 a of the light-emitting devices 105R, 105G,105B, and the transparent electrode 103 is connected also to the contactmetals 104R, 104G, 104B. The light-emitting devices 105R, 105G, 105B aredisposed in the state of being embedded in a device protective resinlayer 106, a back-side resin layer 107 formed on the device protectiveresin layer 106 is provided with vias, and wiring layers 108R, 108G,108B are formed respectively in the vias. The wiring layers 108R, 108G,108B are respectively connected to bumps 109R, 109G, 109B at bottomportions of the vias.

The display substrate 100 is a transparent and flat plate-like memberformed of a glass, a plastic, or the like, which transmits the lightsemitted by the light-emitting devices 105R, 105G, 105B. The adhesivelayer 101 is a layer for adhering the display substrate 100 to theprotective resin layer 102, and can be formed by use of a materialtransmitting the lights emitted from the light-emitting devices 105R,105G, 105B, for example, a thermosetting adhesive. The protective resinlayer 102 is a layer for sealing the transparent electrode layer 103 toprotect the transparent electrode layer 103, and can be formed by use ofa light-transmitting and insulating material, for example, an epoxyresin. With the transparent electrode layer 103 sealed by the protectiveresin layer 102, the transparent electrode layer 103 can be preventedfrom being deformed or deteriorated.

The transparent electrode layer 103 is a layer formed of alight-transmitting and conductive material, and can be made by use of,for example, an ITO ink or the like. The transparent electrode layer 103is formed to be larger in area than the light output surfaces 105 a ofthe light-emitting devices 105R, 105G, 105B, so that the transparentelectrode layer 103 is collectively electrically connected to thelight-emitting devices 105R, 105G, 105B in one pixel. The thickness ofthe transparent electrode layer 103 must only be such a value as tocover the contact metals 104R, 104G, 104B and light emission side wiringlayers 110, which will be described later. For example, the thicknessmay be about 2 to 3 μm. In the case where an ITO ink is used, the ITOink contains about 20 to 30% of an acrylic resin. Therefore, there maybe adopted a structure in which a resin sheet formed of a materialcontaining little organic solvent components is sandwiched between thetransparent electrode layer 103 and the protective resin layer 102. Bysandwiching the resin sheet between the transparent electrode layer 103and the protective resin layer 102, it is possible to prevent mutualdiffusion between the transparent electrode layer 103 and the protectiveresin layer 102, and to prevent the conductivity of the transparentelectrode layer 103 from being deteriorated. Accordingly, the resinsheet functions as a diffusion preventive layer for preventing mutualdiffusion between a component of the transparent electrode layer 103 anda component of the protective resin layer 102.

In the light-emitting apparatus and the image display apparatusaccording to this embodiment, the transparent electrode layer 103 isformed to be larger in area than the light output surfaces 105 a of thelight-emitting devices 105R, 105G, 105B, thereby contriving connectionbetween light emission side wiring layers 110 and the contact metals104R, 104G, 104B. The lights emitted from the light-emitting devices105R, 105G, 105B are emitted to the exterior of the image displayapparatus without being shielded by the transparent electrode layer 103.Therefore, it is possible to enhance light output efficiency, ascompared with the case where the transparent electrode layer 103 isformed with the same dimension of the light output surfaces 105 a, andthereby to enhance the display characteristics of the light-emittingapparatus and of the image display apparatus.

The contact metals 104R, 104G, 104B are metallic layers formed on thelight output surfaces 105 a of the light-emitting devices 105R, 105G,105B, and reduce the contact resistance concerning the contact with thelight output surfaces 105 a. In addition, the contact metals 104R, 104G,104B make contact also with the transparent electrode layer 103, so thatit is necessary to appropriately select the material of the contactmetals according to the material of the transparent electrode layer 103.For example, a noble metal such as platinum (Pt) and gold (Au) is usedfor the contact metals. Where an ITO ink is used for forming thetransparent electrode layer 103, corrosion through an oxidation reactiondue to oxygen contained in the ITO ink can be prevented by forming thecontact metals 104R, 104G, 104B by use of a noble metal. In this case,the contact metals 104R, 104G, 104B may have a multi-layer structure inwhich, for example, a metallic layer of nickel (Ni), aluminum (Al), orcopper (Cu) is formed on the side of the light output surfaces 105 a ofthe light-emitting devices 105R, 105G, 105B, and then a layer of a noblemetal such as platinum and gold is formed at the outermost surfaces.With the outermost surfaces of the contact metals 104R, 104G, 104Bformed of a noble metal, oxidation in the regions of contact with thetransparent electrode layer 103 can be prevented.

In addition, the regions where the contact metals 104R, 104G, 104B areformed are in the vicinity of peripheral portions of the light outputsurfaces 105 a, and are preferably those regions that do not overlapwith the regions where the bumps 109R, 109G, 109B are formed. Thisarrangement is for reducing the amounts of lights shielded by thecontact metals 104R, 104G, 104B at the time of light emission from thelight-emitting devices 105R, 105G, 105B, whereby light output efficiencycan be enhanced.

The light-emitting devices 105R, 105G, 105B are devices for emittinglight in red, green, and blue colors, respectively, and are home-typelight-emitting diodes or hetero-type light-emitting diodes formed bylaminating an n-type semiconductor layer and a p-type semiconductorlayer, for example. While the light-emitting devices 105R, 105G, 105Bare in the shape of chips in the figure, the structure in this exampleis not limitative, and the light-emitting devices 105R, 105G, 105B maybe light-emitting diodes formed by selecting required device structureand materials for making it possible to emit lights at variouswavelengths such as blue, green, yellow, red, infrared, etc. Besides,the light-emitting devices 105R, 105G, 105B may be light-emitting diodesenhanced in light emission efficiency by forming a double heterostructure or a quantum well structure in which an active layer 105 b issandwiched between a p-type clad layer and an n-type clad layer.

While the light-emitting diode 1 is a roughly cylindrical light-emittingdiode in this example, the light-emitting diode 1 may be alight-emitting diode in which the lamination direction of thesemiconductor layers is inclined against the major surface of the deviceforming substrate. The shape of the light-emitting diode is not limitedto the roughly flat plate-like shape as in this example, and may be anyshape. For example, a light-emitting diode in which the sectional deviceshape is tapered, the outside shape is a hexagonal pyramid, or the likemay be adopted. Furthermore, the light-emitting device according to thepresent invention is not limited to a light-emitting diode, and may be alight-emitting device such as a semiconductor laser device. Wherelight-emitting diodes are used as the light-emitting devices 105R, 105G,105B, the driving method for light emission can be driven by an electriccurrent; therefore, good light emission characteristics can be obtainedeven where the sheet resistance is comparatively high due to the use ofthe transparent electrode layer 103.

A device holding resin layer 106 is an insulating resin layer forembedding and fixedly holding the light-emitting devices 105R, 105G,105B therein. The layer 106 is formed by use of a material capable ofbeing hardened (cured) upon irradiation with light, for example, aphotosensitive epoxy resin. The device holding resin layer 106 is formedin an uncured state before the embedding of the light-emitting devices105R, 105G, 105R therein, and is cured (hardened) by exposure after theembedding. A back-side resin layer 107 is an insulating resin layerformed on the device holding resin layer 106, and is provided with viasat positions where bumps 109R, 109G, 109B of the light-emitting devices105R, 105G, 105B are formed. Wiring layers 108R, 108G, 108B are metalliclayers so formed as to cover the inside walls of the vias opened in theback-side resin layer 107 and the bumps 109R, 109G, 109B, and areelectrically connected to the bumps 109R, 109G, 109B in the vias. Thebumps 109R, 109G, 109B are metallic layers formed on the light-emittingdevices 105R, 105G, 105B, are electrically connected to thesemiconductor layers of the light-emitting devices 105R, 105G, 105B andconnected to the wiring layers 108R, 108G, 108B.

As shown in the plan view in FIG. 12B, the wiring layers 108R, 108G,108B are formed in a belt-like shape extending in y-axis direction inthe figure so as to cover the positions where the light-emitting devices105R, 105G, 105B are formed, respectively. In addition, in the planewhere the contact metals 104R, 104G, 104B are formed, the light emissionside wiring layers 110, which will be described later, are formed in abelt-like shape extending in x-axis direction in the figure, and iselectrically connected to the transparent electrode layer 103. The lightemission side wiring layers 110 also make contact with the transparentelectrode layer 103, like the contact metals 104R, 104G, 104B.Therefore, the material of the light emission side wiring layers 110must be appropriately selected according to the material of thetransparent electrode layer 103, and is, for example, a noble metal suchas platinum and gold. Where the transparent electrode layer 103 isformed by use of an ITO ink, corrosion through an oxidation reaction dueto oxygen contained in the ITO ink can be prevented by forming the lightemission side wiring layers 110 by use of a noble metal. In this case,the light emission side wiring layers 110 may have a multi-layerstructure in which, for example, a nickel layer is formed, and then alayer of a noble metal such as platinum and gold is formed at theoutermost surface. With the outermost surfaces of the light emissionside wiring layers 110 formed of a noble metal, it is possible toprevent oxidation in the regions of contact with the transparentelectrode layer 103.

As shown in FIG. 12B, the regions where the light emission side wiringlayers 110, which will be described later, are formed are outside theregions of the light output surfaces 105 a of the light-emitting devices105R, 105G, 105B, and do not overlap with the locations where thelight-emitting devices 105R, 105G, 105B are formed, so that the lightemission side wiring layers 110 do not make direct contact with thecontact metals 104R, 104G, 104B. However, both the light emission sidewiring layers 110 and the contact metals 104R, 104G, 104B are in contactwith the transparent electrode layer 103. Therefore, they areelectrically connected to each other through the transparent electrodelayer 103. Since the light emission side wiring layers 110 are so formedas not to overlap with the light-emitting devices 105R, 105G, 105B, thelights emitted from the light output surfaces 105 a at the time of lightemission from the light-emitting devices 105R, 105G, 105B are notshielded by the light emission side wiring layers 110, so that it ispossible to enhance light output efficiency and to perform lightemission and image display with good display characteristics.

In addition, outside the pixel region of the back-side resin layer 107and the device holding resin layer 106, there is opened a lead viaextending from the plane of formation of the wiring layers 108R, 108G,108B and reaching the light emission side wiring layer 110. A metalliclayer is formed in the lead via, to form a lead pad 111. The lead pad111 is formed by use of a metal, which is ordinarily used as an electricwiring, for example, copper. Since the lead pad 111 is connected to thelight emission side wiring layer 110 through the via and the lightemission side wiring layer 110 is electrically connected to the wiringlayers 108R, 108G, 108B through the transparent electrode layer 103, thelight output surfaces 105 a of the light-emitting devices 105R, 105G,105B are electrically connected to the lead pad 111. As a result, when avoltage is impressed between any one of the wiring layers 108R, 108G,108B and the lead pad 111, an electric current is passed to thecorresponding light-emitting device 105R, 105G, or 105B, which emitslight at a predetermined wavelength.

While the structure of the light-emitting apparatus, which is one pixelconstituted of the light-emitting devices 105R, 105G, 105B for lightemission in red, green, and blue is shown in FIGS. 12A and 12B, in anactual image display apparatus the pixels having the structure shown inFIGS. 12A and 12B are arranged in a row direction and a column directionon the display substrate 100. Besides, the wiring layers 108R, 108G,108B and the light emission side wiring layer 110 extend respectively inthe column direction and the row direction on the display substrate 100,and the wiring layers may each be formed as a common wiring for thepixels disposed in the same row direction and for the pixels disposed inthe same column direction. Where the wiring layers 108R, 108G, 108B andthe light emission side wiring layers 110 are formed as common wiringsin the image display apparatus, it is possible to obtain a passivematrix drive type or active matrix drive type image display apparatus inwhich the plurality of wiring layers 108R, 108G, 108B formed in thecolumn direction are column wirings and the plurality of light emissionside wiring layers 110 formed in the row direction are row wirings.

Next, the method of manufacturing the light-emitting apparatus and theimage display apparatus according to this embodiment will be describedin detail, referring to FIGS. 13A and 13B to 29A and 29B. Incidentally,while the light-emitting apparatus, which is the structure per pixel inthe image display apparatus, will be shown in the following description,the image display apparatus includes a plurality of pixels arranged inthe row direction and the column direction, and the individual pixelshave the same structure.

First, as shown in the sectional view in FIG. 13A and the plan view inFIG. 13B, an embedding substrate 200, which is a flat plate-like member,is prepared, and alignment marks 201R, 201G, 201B are formed atpredetermined positions on the embedding substrate 200. FIG. 13A is asectional view taken along the broken line direction in FIG. 13B. As theembedding substrate 200, for example, a disk form sapphire substratewith a diameter of about 2 in can be used. It suffices that the materialof the embedding substrate 200 has a flat surface and a predeterminedrigidity, and the shape thereof may be any of various shapes such as arectangular shape. The alignment marks 201R, 201G, 201B can be formed,for example, by vapor-depositing titanium on the embedding substrate 200and conducting lift-off to leave titanium in predetermined regions. Thealignment marks 201R, 201G, 201B are formed one in each predeterminedregion in the region of one pixel, and are used as marks for alignmentin disposing the light-emitting devices in a later step. Since thealignment marks 201R, 201G, 201B are marks for alignment, it sufficesfor them to have such a thickness as to enable discrimination thereoffrom the other regions. For example, the alignment marks may be in athin film form with a thickness of about 10 nm. The region correspondingto one pixel shown in FIG. 13B is, for example, a square with each sidebeing about 150 μm in length.

Next, as shown in the sectional view in FIG. 14A and the plan view inFIG. 14B, an embedding resin layer 202 is formed on the side, where thealignment marks 201R, 201G, 201B are formed, of the embedding substrate200. FIG. 14A is a sectional view taken along the broken line directionin FIG. 14B. The embedding resin layer 202 is formed by use of a resin,which has such a degree of plasticity that the light-emitting devices,can be embedded therein and which can be cured by light exposure,heating, or the like. For example, the embedding resin layer 202 may beformed by applying a photosensitive epoxy resin by a laminatingoperation. The thickness of the embedding resin layer 202 must be notless than the height of the light-emitting devices to be embedded. Forexample, the embedding resin layer 202 is formed in a thickness of about15 μm to about 30 μm. At this stage, since the light-emitting devicesare not yet embedded in the embedding resin layer 202, the embeddingresin layer 202 is in a plastic state.

Next, as shown in the sectional view in FIG. 15A and the plan view inFIG. 15B, a mask 203 is arranged near the surface of the embedding resinlayer 202, light exposure is applied to the regions not covered with themask 203, to cure predetermined regions of the embedding resin layer202, thereby forming separation walls 204 extending from the surface ofthe embedding resin layer 202 to the embedding substrate 200. FIG. 15Ais a sectional view taken along the broken line direction in FIG. 15B.As shown in the figures, the separation walls 204 are formed in theshape of frames such as to surround the alignment marks 201R, 201G, 201Bin the pixel, whereby the region of the pixel is divided on the basis ofeach light-emitting device embedding region. With the separation walls204 thus formed, it is possible to obviate the problem that theembedding resin layer 202 would flow to cause a positional stagger inthe already embedded light-emitting device, at the time of embedding thelight-emitting devices into the embedding resin layer 202 in a laterstep. At this stage, the preparation for embedding the light-emittingdevices into the embedding resin layer 202 is completed.

Separately from the preparation of the embedding substrate 200 and theembedding resin layer 202 as above-described, as shown in the sectionalview in FIG. 16A and the plan view in FIG. 16B, a transfer substrate 205with a plurality of light-emitting devices 105R arranged thereon isprepared, and the light-emitting devices 105R are selectivelytransferred onto a relay substrate 206 coated with a silicone layer 207.FIG. 16A is a sectional view taken along the broken line direction inFIG. 16B. As the transfer substrate 205, for example, a sapphiresubstrate is used. The light-emitting devices 105R arranged on thetransfer substrate 205 may be those which have been crystal-grown onanother substrate and been transferred onto the transfer substrate 205,and the light-emitting devices 105R are adhered to the transfersubstrate 205 by use of an adhesive or the like. The selective transferof the light-emitting devices 105R from the transfer substrate 205 ontothe relay substrate 206 can be carried out by a method in whichpredetermined ones of the light-emitting devices 105R are irradiatedwith laser beams from the side of the transfer substrate 205 by use ofan excimer laser or the like so as to weaken the adhesive force betweenthe light-emitting devices 105R and the transfer substrate 205.

The light-emitting devices 105R thus transferred are the devices locatedat positions spaced from each other by predetermined intervals in therow direction and the column direction on the transfer substrate 205, asshown in FIG. 16B, and the light-emitting devices 105R are transferredone for each region, corresponding to one pixel, of the embeddingsubstrate 200. For example, where the region corresponding to one pixelon the embedding substrate 200 is a square with each side being about150 μm, the light-emitting devices 105R transferred are also transferredat an interval of about 150 μm. The light-emitting devices 105Rirradiated with the laser beams are exfoliated from the transfersubstrate 205 and transferred onto the relay substrate 206, due to alowering in the adhesive force of the adhesive. In this case, the lightoutput surfaces 105 a of the light-emitting devices 105R are broughtinto contact with the silicone layer 207, so that the light-emittingdevices 105R are held on the relay substrate 206 by the tack of thesilicone layer 207. While the description has been made here only of thelight-emitting devices 105R for emitting light in red color, as shown inthe figures, the light-emitting devices 105G for emitting light in greencolor and the light-emitting devices 105B for emitting light in bluecolor are also separately transferred selectively from the transfersubstrate 205 onto the relay substrate 206 in the same manner as above.

Next, as shown in the sectional view in FIG. 17A and the plan view inFIG. 17B, the light-emitting devices 105R held on the relay substrate206 are embedded into the embedding resin layer 202. FIG. 17A is asectional view taken along the broken line direction in FIG. 17B. Inthis case, since the embedding substrate 200 is provided with thealignment marks 201R, the positional relationship between the relaysubstrate 206 and the embedding substrate 200 is so regulated that thelight-emitting devices 105R are located at the positions of thealignment marks 201R. When the positions of the alignment marks 201R andthe light-emitting devices 105R have come to overlap with each other,the embedding substrate 200 and the relay substrate 206 are broughtcloser to each other, and the light-emitting devices 105R are embeddedinto the embedding resin layer 202. Since the embedding resin layer 202is surrounded by the partially cured separation walls 204, in theprocess of embedding the light-emitting devices 105R into the embeddingresin layer 202 as above-mentioned, the embedding resin layer 202 in theoutside of the separation walls 204 can be prevented from flowing.Besides, the step of embedding the light-emitting devices 105R into theembedding resin layer 202 may be so carried out that the light-emittingdevices 105R are embedded by a single embedding operation.Alternatively, the light-emitting devices 105R may be exfoliated fromthe relay substrate 206 in the condition of being embedded partly, andthen they may be embedded further by a laminating operation or the liketo such an extent that the light output surfaces 105 a of thelight-emitting devices 105R become substantially flush with the surfaceof the embedding resin layer 202.

Next, as shown in the sectional view in FIG. 18A and the plan view inFIG. 18B, after the light-emitting devices 105R are embedded to such anextent that the light output surfaces 105 a of the light-emittingdevices 105R are substantially flush with the surface of the embeddingresin layer 202, the embedding resin layer 202 in the regions where thelight-emitting devices 105R have been embedded is cured by lightexposure, to form a device holding resin layer 106. FIG. 18A is asectional view taken along the broken line direction in FIG. 18B. Bycuring the embedding resin layer 202 to form the device holding resinlayer 106, the positions of the light-emitting devices 105R in pixelsare fixed. As shown in the sectional view in FIG. 19A and the plan viewin FIG. 19B, the light-emitting devices 105G and 105B are embedded intothe embedding resin layer 202 at the positions of the alignment marks201G and 201B, and cured by light exposure to form device holding resinlayers 106, in the same procedure as shown in FIGS. 16A and 16B to 18Aand 18B. FIG. 19A is a sectional view taken along the broken linedirection in FIG. 19B. When the light-emitting devices 105R, 105G, 105Bare transferred onto the relay substrate 206 by the selective transfersuch as to provide device intervals equal to the pixel size as shown inFIG. 16B, the devices can be collectively aligned and embedded for aplurality of pixels.

Next, as shown in the lateral sectional view in FIG. 20A and the planview in FIG. 20B, electrode separation walls 208 are formed on thedevice holding resin layers 106. FIG. 20A is a sectional view of theimage display apparatus as viewed along arrow A in FIG. 19A, namely, asviewed in a direction at 90 degrees against the sectional views shown inFIGS. 12A and 12B to 19A and 19B, and is a sectional view taken alongthe broken line direction in FIG. 20B and viewed from the same directionas arrow A in FIG. 20B. The electrode separation walls 208 can be formedby a method in which a resist film is applied onto the device holdingresin layers 106, then predetermined regions thereof are hardened andthe unhardened regions thereof are removed, by photolithographictechnique. The hardened resist film becomes the electrode separationwalls 208, and the removed regions constitute opening portions such asto expose the light output surfaces 105 a and the contact metals 104R,104G, 104B of the light-emitting devices 105R, 105G, 105B.

The electrode separation walls 208 are patterns formed outside theregion of the transparent electrode layer in each pixel. With theelectrode separation walls 208 thus formed, a step is generated betweenthe surface of the device holding resin layers 106 and the surface ofthe electrode separation walls 208. The regions where the device holdingresin layers 106 are exposed at this stage are regions where thetransparent electrode layer 103 is to be formed in a later step. Asshown in FIG. 20B, the regions where the electrode separation walls 208are formed are outside the regions where the light-emitting devices105R, 105G, 105B are embedded, and the regions where the electrodeseparation walls 208 are not formed are in a belt-like shape, and eachinclude the light-emitting devices 105R, 105G, 105B collectively.Besides, the regions where the electrode separation walls 208 are notformed are somewhat larger than the regions where the light-emittingdevices 105R, 105G, 105B are formed, to such an extent that lightemission side wiring layers can be formed in a later step. Therefore,even upon formation of the electrode separation walls 208, the lightoutput surfaces 105 a of the light-emitting devices 105R, 105G, 105B areexposed from the device holding resin layers 106, and the contact metals104R, 104G, 104B are also exposed.

Next, as shown in the lateral sectional view in FIG. 21A and the planview in FIG. 21B, the light emission side wiring layers 110 are formedin the regions where the device holding resin layers 106 are exposed andthe electrode separation walls 208 are not formed. FIG. 21A is asectional view taken along the broken line direction in FIG. 21B. Thelight emission side wiring layers 110 are formed in a belt-like shapewith a width of 50 μm, for example, so as to cross each pixel in theleft-right direction in FIG. 21B, is not formed at the positions wherethe light-emitting devices 105R, 105G, 105B are embedded, and is soformed as not to make contact with the contact metals 104R, 104G, 104B.Since the light emission side wiring layers 110 are so formed as not tooverlap with the light-emitting devices 105R, 105G, 105B, the lightsemitted from the light-emitting devices 105R, 105G, 105B and radiatedfrom the light output surfaces 105 a are not shielded by the lightemission side wiring layers 110, so that it is possible to enhance lightoutput efficiency and to perform an image display with good displaycharacteristics. In addition, since it is unnecessary to set the lightemission side wiring layers 110 in contact with the contact metals 104R,104G, 104B, it is possible to lower the positioning accuracy in formingthe light emission side wiring layers 110 and to enhance the operatingefficiency, as compared with the case of setting the light emission sidewiring layers 110 in contact with the minute contact metals 104R, 104G,104B. While an example of forming the light emission side wiring layers110 after formation of the electrode separation walls 208 has beendescribed here, the electrode separation walls 208 may be formed afterformation of the light emission side wiring layers 110.

The light emission side wiring layer 110 is formed, for example, by amethod in which a titanium (Ti) layer in a thickness of about 50 nm isformed on the device holding resin layers 106 by sputtering, then Ti islaminated thereon in a thickness of about 10 nm by vapor deposition, andgold (Au) is laminated in a thickness of about 0.5 μm by vapordeposition. In this case, Au is exposed at the outermost surfaces of thelight emission side wiring layers 110, and the material coming intocontact with the transparent electrode layer 103 in a later step isgold, which is a noble metal. With the outermost surfaces of the lightemission side wiring layers 110 formed of the noble metal, it ispossible to prevent the light emission side wiring layers 110 from beingcorroded due to oxidation or the like.

Next, as shown in the lateral sectional view in FIG. 22A and the planview in FIG. 22B, an ITO ink is applied onto the device holding resinlayers 106 and onto the electrode separation walls 208 by spin coating,and is hardened by baking, to form the transparent electrode layer 103.FIG. 22A is a sectional view taken along the broken line direction inFIG. 22B. For application of the ITO ink, not only spin coating but alsoa screen printing technique, jetting of the ITO ink by an ink jettechnique, and the like may be used. At this stage, the transparentelectrode layer 103 is formed on the whole surfaces of pixels so as tocover the device holding resin layers 106, the electrode separationwalls 208, the light output surfaces 105 a of the light-emitting devices105R, 105G, 105B, the contact metals 104R, 104G, 104B, and the lightemission side wiring layers 110.

Since the transparent electrode layer 103 is formed in contact with thecontact metals 104R, 104G, 104B and the light emission side wiringlayers 110, the contact metals 104R, 104G, 104B and the light emissionside wiring layers 110 are electrically connected to each other throughthe transparent electrode layer 103. It is necessary to form thetransparent electrode layer 103 in such a thickness as to cover thecontact metals 104R, 104G, 104B and the light emission side wiringlayers 110. The thickness may be about 5 μm in the case where the lightemission side wring layer 110 is formed by laminating Ti/Ti/Au in athickness combination of 50 nm/10 nm/0.5 μm. With the light emissionside wiring layers 110 electrically connected to the contact metals104R, 104G, 104B through the transparent electrode layer 103, theelectrical connection between the light emission side wiring layers 110and the contact metals 104R, 104G, 104B can be secured through thetransparent electrode layer 103, which is formed over a wide range.Therefore, since the transparent electrode layer 103 is so formed as tosecurely cover the contact metals 104R, 104G, 104B, it is possible tolower the accuracy of the positions of embedding the light-emittingdevices 105R, 105G, 105B and the positions of forming the contact metals104R, 104G, 104B in each pixel, and to contrive a higher operatingefficiency. In the present invention, the thickness of the transparentelectrode layer 103 can be enlarged up to about the thickness of theelectrode separation walls 208. Therefore, it is possible to easilysecure electrical connection between the transparent electrode layer 103and the contact metals 104R, 104G, 104B while easily coping with notonly the positional accuracy in the horizontal directions in each pixelbut also the positional staggers in the height direction, which may begenerated upon embedding the light-emitting devices 105R, 105G, 105B.

Next, as shown in the lateral sectional view in FIG. 23A and the planview in FIG. 23B, the transparent electrode layer 103 is polished byChemical Mechanical Polishing (CMP) by use of the Damascene process, tosuch an extent that the surfaces of the electrode separation walls 208are exposed. FIG. 23A is a sectional view taken along the broken linedirection in FIG. 23B. Where the transparent electrode layer 103 issofter than the electrode separation walls 208, the transparentelectrode layer 103 upon polishing is thinner than the electrodeseparation walls 208 as shown in the figure. Therefore, it is necessaryto set the thickness of the electrode separation walls 208 at such anextent that the thickness of the transparent electrode layer 103 uponpolishing is sufficiently secured. In addition, the transparentelectrode layer 103 upon polishing must have such a thickness as toenable connection between the contact metals 104R, 104G, 104B and thelight emission side wiring layers 110. In view of this, for example, thetransparent electrode layer 103 is formed in a thickness of about 5 μmbefore polishing, and a thickness of about 3 μm is maintained afterpolishing. Where a minute amount of an ITO ink is applied by use of theink jet technique at the time of forming the transparent electrode layer103 as above-mentioned, it is possible to regulate the amount of the ITOink applied, thereby ensuring that the transparent electrode layer 103will not be laminated on the electrode separation walls 208.Accordingly, it is possible to omit the step of polishing thetransparent electrode layer 103.

Next, as shown in the lateral sectional view in FIG. 24A and the planview in FIG. 24B, an epoxy resin is laminated on the transparentelectrode layer 103 and the electrode separation walls 208 by alaminating operation, to form a protective resin layer 102. FIG. 24A isa sectional view taken along the broken line direction in FIG. 24B. Insome cases, the surface of the transparent electrode layer 103 uponpolishing may be rugged. By forming the protective resin layer 102 onthe transparent electrode layer 103 and the electrode separation walls208, however, it is possible to render the surface of the protectiveresin layer 102 flat, and to cover, seal, and protect the transparentelectrode layer 103.

Next, as shown in the lateral sectional view in FIG. 25A and the planview in FIG. 25B, a display substrate 100 is adhered to the protectiveresin layer 102 with an adhesive layer 101 in vacuum, by use of a vacuumadhesion apparatus. FIG. 25A is a sectional view taken along the brokenline direction in FIG. 25B. With the adhesion conducted in vacuum, it ispossible to prevent bubbles from entering between the display substrate100 and the protective resin layer 102. In this case, a variety ofadhesive layers 101 can be used. For example, a thermosetting adhesivemay be used, and the adhesive layer 101 may be cured by heating. Withthe protective resin layer 102 formed on the transparent electrode layer103 and the electrode separation walls 208, it is possible to render thesurface of the protective resin layer 102 flat, irrespective of thepresence or absence of ruggedness in the surface of the transparentelectrode layer 103, and it is therefore easy to adhere the flat andhard display substrate 100 to the protective resin layer 102.

Next, as shown in the sectional view in FIG. 26A and the top plan viewin FIG. 26B, the assembly is irradiated with excimer laser beams fromthe side of the embedding substrate 200, to cause exfoliation at theinterface between the embedding substrate 200 and the device holdingresin layers 106 through laser ablation. FIG. 26A is a sectional viewtaken along the broken line direction in FIG. 26B. FIG. 26B is a planview of one pixel in the image display apparatus as viewed from the sideof the device holding resin layers 106. Upon irradiation with the laserbeams, a reaction of thermal melting of the device holding resin layers106 or the like occurs at the interface between the embedding substrate200 and the device holding resin layers 106, it is possible to easilyrelease the device holding resin layers 106 from the embedding substrate200, thereby exposing the alignment marks 201R, 201G, 201B.

Next, as shown in the sectional view in FIG. 27A and the top plan viewin FIG. 27B, the device holding resin layers 106 are etched from theside of the alignment marks 201R, 201G, 201B, to expose the bumps 109R,109G, 109B of the light-emitting devices 105R, 105G, 105B. FIG. 27A is asectional view taken along the broken line direction in FIG. 27B. Inthis case, the removal of the device holding resin layers 106 isconducted to such an extent that the bumps 109R, 109G, 109B protrudefrom the device holding resin layers 106. In order to cause the bumps109R, 109G, 109B to protrude, the resin removed by the etching includesnot only the resin of the device holding resin layers 106 but also theresin with which the main bodies of the light-emitting devices 105R,105G, 105B are packaged.

Next, as shown in the sectional view in FIG. 28A and the top plan viewof FIG. 28B, a back-side resin layer 107 is laminated on the deviceholding resin layers 106 with the bumps 109R, 109G, 109B exposed, andthen vias 112R, 112G, 112B for exposing the bumps 109R, 109G, 109B areopened by a photolithographic technique. FIG. 28A is a sectional viewtaken along the broken line direction in FIG. 28B. With the back-sideresin layer 107 thus formed, the bumps 109R, 109G, 109B are locatedbelow the surface of the back-side resin layer 107, and are exposed fromthe bias 112R, 112G, 112B, which are formed isolatedly. The bumps 109R,109G, 109B are isolated by the presence of the back-side resin layer 107and the vias 112R, 112G, 112B, whereby it is possible to restrain thegeneration of shortcircuit troubles due to contact between adjacentwirings, at the time of forming wiring layers 108R, 108G, 108B in alater step.

Next, as shown in the sectional view in FIG. 29A and the top plan viewin FIG. 29B, in the outside of the region of the pixels in the imagedisplay apparatus, a lead via 113 extending from the back-side resinlayer 107 to the light emission side wiring layer 110 is opened byetching or the like. FIG. 29A is a sectional view taken along the brokenline direction in FIG. 29B. Since the light emission side wiring layer110 is formed with a large width of about 50 μm, for example, asexemplified in FIGS. 21A and 21B, it suffices that the positionalaccuracy in opening the lead via 113 is on the order of a fewmicrometers.

Finally, as shown in the sectional view in FIG. 30A and the top planview in FIG. 30B, wiring layers 108R, 108G, 108B are formed so as tocover the vias 112R, 112G, 112B, and a lead pad 111 is formed so as tofill up the lead via 113. FIG. 30A is a sectional view taken along thebroken line direction in FIG. 30B. The wiring layers 108R, 108G, 108Band the lead pad 111 can be formed, for example, by a method in whichtitanium (Ti) and copper (Cu) as seed metals are deposited bysputtering, then copper is built up by plating, and patterning isconducted by wet etching.

By use of the method of manufacturing a light-emitting apparatus and themethod of manufacturing an image display apparatus described abovereferring to FIGS. 13A and 13B to 30A and 30B, it is possible to obtainan image display apparatus in which a plurality of pixels having thestructure shown in FIGS. 30A and 30B are arranged in the row directionand the column direction. Where the wiring layers 108R, 108G, 108B andthe light emission side wiring layers 110 are formed as common wiringsin the image display apparatus, it is possible to obtain a passivematrix drive type or active matrix drive type image display apparatus inwhich the plurality of wiring layers 108R, 108G, 108B formed in thecolumn direction constitute column wirings and the plurality of lightemission side wiring layers 110 arranged in the row direction constituterow wirings.

When the method of manufacturing a light-emitting apparatus and themethod of manufacturing an image display apparatus described in thisembodiment are used, it is unnecessary to set the light emission sidewiring layers 110 in contact with the contact metals 104R, 104G, 104B,so that it is possible to lower the positional accuracy in forming thelight emission side wiring layers 110 and therefore to enhance operatingefficiency, as compared with the case where the light emission sidewiring layer 110 are set in contact with the minute contact metals 104R,104G, 104B.

In the light-emitting apparatus and the image display apparatusaccording to this embodiment, the transparent electrode layer 103 isformed to be larger in area than the light output surfaces 105 a of thelight-emitting devices 105R, 105G, 105B, to achieve connection betweenthe light emission side wiring layers 110 and the contact metals 104R,104G, 104B. Since the lights emitted from the light-emitting devices105R, 105G, 105B are radiated to the exterior of the image displayapparatus without being shielded by the transparent electrode layer 103,it is possible to enhance light output efficiency and to enhance displaycharacteristics of the image display apparatus, as compared with thecase where the transparent electrode layer 103 is formed with the samedimension of the light output surfaces 105 a.

By forming the outermost surfaces of the contact metals 104R, 104G, 104Bof a noble metal, it is possible to prevent oxidation of the contactmetals 104R, 104G, 104B in the regions of contact with the transparentelectrode layer 103. Besides, by forming the outermost surfaces of thelight emission side wiring layers 110 of a noble metal, it is possibleto prevent oxidation of the light emission side wiring layers 110 in theregions of contact with the transparent electrode layer 103. This makesit possible to prevent the contact metals and the light emission sidewiring layers from being deteriorated due to corrosion with the resultof an increase in the electric resistance thereof.

It is desirable that the regions where the contact metals 104R, 104G,104B are formed are in the vicinity of peripheral portions of the lightoutput surfaces 105 a, and are preferably in the regions that do notoverlap with the regions where the bumps 109R, 109G, 109B are formed.This is for reducing the amounts of lights shielded by the contactmetals 104R, 104G, 104B at the time of light emission from thelight-emitting devices 105R, 105G, 105B, and makes it possible toenhance light output efficiency. Since the light emission side wiringlayers 110 are so formed as not to overlap with the light-emittingdevices 105R, 105G, 105B, the lights emitted from the light-emittingdevices 105R, 105G, 105B and radiated from the light output surfaces 105a are not shielded by the light emission side wiring layers 110, so thatit is possible to enhance the light output efficiency and to performlight emission and image display with good display characteristics.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present invention andwithout diminishing its intended advantages. It is therefore intendedthat such changes and modifications be covered by the appended claims.

1. A method of manufacturing a light-emitting device, the methodcomprising: transferring a light-emitting device main body having alight output surface onto a resin portion so as to expose the lightoutput surface; forming a resist film on the light output surface andthe surface of the resin portion; providing the resist film with anopening portion larger in size than the light output surface so that theopening portion fronts on the light output surface; and forming atransparent electrode in the opening portion so that the transparentelectrode is connected directly to an area of the light output surface.2. The method of manufacturing a light-emitting device as set forth inclaim 1, wherein the opening portion is so formed as to front on awiring for supplying electric power to the light-emitting device mainbody, and the light output surface and the wiring are connected directlyto each other through the transparent electrode.
 3. A method ofmanufacturing a light-emitting device, the method comprising: forming aresist film on a light output surface of a light-emitting device mainbody; providing the resist film with an opening portion larger in sizethan the light output surface so that the opening portion fronts on thelight output surface; and forming a transparent electrode in the openingportion so that the transparent electrode is connected directly to awhole area of the light output surface.
 4. A method of manufacturing animage display apparatus, the method comprising: transferring a pluralityof light-emitting device main bodies each having a light output surfaceonto a resin portion so as to expose the light output surfaces; forminga resist film on the light output surfaces and the surface of the resinportion; providing the resist film with an opening portion larger insize than the light output surfaces so that the opening portion frontson the light output surfaces; and forming a transparent electrode in theopening portion so that the transparent electrode is connected directlyto an area of the light output surfaces.
 5. The method of manufacturingan image display apparatus as set forth in claim 4, wherein the openingportion is so formed as to front on a wiring for supplying electricpower to the plurality of light-emitting device main bodies, and thelight output surfaces and the wiring are connected to each othercollectively through the transparent electrode.
 6. A method ofmanufacturing a light-emitting apparatus the method comprising:transferring a light-emitting device main body having a light outputsurface onto a resin portion so as to expose the light output surface;forming an electrode separation wall on the surface of the resinportion; providing the electrode separation wall with an opening portionlarger in size than the light output surface so that the opening portionfronts on the light output surface; forming a wiring layer on a surfaceof the resin portion in an inside of the opening portion; and forming atransparent electrode in the opening portion so that the transparentelectrode is connected directly to a contact metal formed on the lightoutput surface and to the wiring layer.
 7. The method of manufacturing alight-emitting apparatus as set forth in claim 6, wherein the wiringlayer is formed outside the region of the light output surface.
 8. Themethod of manufacturing a light-emitting apparatus as set forth in claim6, wherein after a transparent electrode material is so applied as tocover the opening portion and the electrode separation wall and ishardened, the transparent electrode material is polished to expose thesurface of the electrode separation wall, thereby forming thetransparent electrode.
 9. The method of manufacturing a light-emittingapparatus as set forth in claim 6, wherein the transparent electrode isformed by jetting a transparent electrode material to the openingportion by an ink jet technique, and hardening the transparent electrodematerial.
 10. The method of manufacturing a light-emitting apparatus asset forth in claim 6, wherein the transparent electrode is formed byapplying a transparent electrode material to the opening portion byscreen printing, and hardening the transparent electrode material. 11.The method of manufacturing a light-emitting apparatus as set forth inclaim 6, wherein a plurality of the light-emitting device main bodiesare transferred onto the resin portion, and the transparent electrode isformed collectively so as to cover contact metals formed on the lightoutput surfaces of a plurality of the light-emitting devices.
 12. Themethod of manufacturing a light-emitting apparatus as set forth in claim6, wherein the wiring layer is formed by forming a metallic layer in aninside of the opening portion, and thereafter laminating a noble metallayer on the metallic layer.
 13. The method of manufacturing alight-emitting apparatus as set forth in claim 6, further comprising astep of forming a protective resin layer for protecting the transparentelectrode, so as to cover the transparent electrode.
 14. The method ofmanufacturing a light-emitting apparatus as set forth in claim 13,further comprising a step of forming a diffusion preventive layer forpreventing mutual diffusion of a component of the protective resin layerand a component of the transparent electrode, on the surface of thetransparent electrode.
 15. A method of manufacturing an image displayapparatus, comprising: transferring a plurality of light-emitting devicemain bodies each having a light output surface onto a resin portion soas to expose the light output surfaces; forming an electrode separationwall on a surface of the resin portion; providing the electrodeseparation wall with an opening portion larger in size than the lightoutput surfaces so that the opening portion fronts on the light outputsurfaces; forming a wiring layer on a surface of the resin portion in aninside of the opening portion; and forming a transparent electrode inthe opening portion so that the transparent electrode is connecteddirectly to contact metals formed on the light output surfaces and tothe wiring layer.